ࡱ; *  !"#$%&'()*+,-.0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~Root Entry   FMicrosoft Word-Dokument MSWordDocWord.Document.89qOh+'0d px  ( 4 @ L X1DOC and Java: Project Requirements/SpecificationUniversity of ConnecticutNormalK [ZZNormal 1$A$*$/B*OJQJCJmH sH PJ^JaJnHtH_H9HH Heading 1@& & F & Fd$CJ5BB Heading 2@& & F & F$CJ5RR Heading 3@& & F & F<$OJQJCJ^JZZ Heading 4.@& & F & Fd$a$^]`$CJ5JJ Heading 5"@& & F & Fd$a$$5HH Heading 6@& & F & F$a$$CJ5"" WW8Num1z0.. WW8Num2z0 OJQJ^J.. WW8Num3z0 OJQJ^J"!" WW8Num4z0.1. WW8Num5z0 OJQJ^J.A. WW8Num6z0 OJQJ^J"Q" WW8Num7z0.a. WW8Num8z0 OJQJ^J"q" WW8Num9z0$$ WW8Num10z0$$ WW8Num11z0$$ WW8Num12z000 WW8Num13z0 OJQJ^J00 WW8Num14z0 OJQJ^J00 WW8Num15z0 OJQJ^J00 WW8Num16z0 OJQJ^J$$ WW8Num17z0$$ WW8Num18z000 WW8Num19z0 OJQJ^J0!0 WW8Num20z0 OJQJ^J010 WW8Num21z0 OJQJ^J0A0 WW8Num22z0 OJQJ^J0Q0 WW8Num23z0 OJQJ^J0a0 WW8Num24z0 OJQJ^J0q0 WW8Num25z0 OJQJ^J00 WW8Num26z0 OJQJ^J00 WW8Num27z0 OJQJ^J88 WW8Num28z0OJQJnH tH ^J$$ WW8Num29z0$$ WW8Num30z000 WW8Num31z0 OJQJ^J00 WW8Num32z0 OJQJ^J00 WW8Num33z0 OJQJ^J00 WW8Num34z0 OJQJ^J00 WW8Num35z0 OJQJ^J0!0 WW8Num36z0 OJQJ^J010 WW8Num37z0 OJQJ^J0A0 WW8Num38z0 OJQJ^J0Q0 WW8Num39z0 OJQJ^J$a$ WW8Num40z0$q$ WW8Num41z0$$ WW8Num42z0$$ WW8Num43z0<<Default Paragraph Font6U6 Internet Link B*ph>*((CODEOJQJCJ^JFVFVisited Internet Link B* ph>*66Heading>d$a$CJ50B0 Text Body?dCJ / List@^J@"@Caption Axx $CJ6^JaJ]&"&IndexB $^JJC2JText Body IndentCd^]`CJ2J2SubtitleDdCJ5NRNBody Text Indent 2Edh^]`0CJ0b0 Body Text 2F$a$NrNBody Text Indent 3Gd^]`hCJ.. Body Text 3HCJff Preformatted(I # ~= z9!v%OJQJnH tH ^J00Frame ContentsJ &:BPXgny'<?BZr8TU   !#$+,0123456 &:BPXgny'<?BZr8TU     PFh4izZfhN@Lh|f @P#B3SdNipܼNL      !"#$%&'0"0$0)Ux@$o'Rz'g'u$e<V4m ?@,\0Ul"Cp,RO8].UY,ji8uS::XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX8617@~$16"$(     f0e0e5%C"    f0e0e5%C"    f0e0e5%C"    f0e0e5%C"    f0e0e5%C" zB  BD$?C"B   fD$?C"B    fD$?C"    f0e0e5%C"     f0e0e5%C" B    fD$?C"B    fD$?C"   f0e0e5%C"    f 0e0e5%C"  B   fD$?C"B   fD$?C"   f 0e0e5%C"     f 0e0e5%C"     f 0e0e5%C"  B   fD$?C"B   fD$?C"   f 0e0e5%C"     f0e0e5%C" B   fD$?C"B   fD$?C" b ` 3 C"  C x0e0e$?0 P  C x0e0e$?  C x0e0e$??   T$?`     0e0e$ * *?`A/ ! C x0e0e$?PA  " T$? # C x0e0e$?A $ C x0e0e$?A2 % T$?P@2 & T$?PrB ' BD$?PPrB ( BD$?B )  fD$? aa * T$?  + C x0e0e$?A   , C x0e0e$?A  B -  fD$?aOaB .  fD$?  B /B  fD$?  0 C x0e0e$?1 1  f0e0e5%C"  2  f0e0e5%C"  3 NC"  4 NC"  5 HC"  6 NC" < C 556F8MiNiOiPiQiRiiiiiiiiiiNjOjPjQjRjTjUjVjWjXjW1Py1451o#o5t3@G T4) t2 446t04th, tpTTtTTt t , tkt` k_t (c Bt  t  tHcBtcgBt`Pt`Ptt /tx' tHtgt /Mt t t`Pt`Pt`t _987348088 _98732253300     ^`P^@`@^`0^```^`^`^`^``^0`0^h`h[] ^h`hOJQJ^J ^h`hOJQJ^J ^h`hOJQJ^J ^h`hOJQJ^J^h`h) ^h`hOJQJ^J^h`h. ^h`hOJQJ^J ^h`hOJQJ^J ^h`hOJQJ^J ^h`hOJQJ^J ^h`hOJQJ^J ^h`hOJQJ^J ^h`hOJQJ^J ^h`hOJQJ^J^h`hOJQJnH tH ^J^8`8.^`OJQJ- ^h`hOJQJ^J ^h`hOJQJ^J ^h`hOJQJ^J ^h`hOJQJ^J ^h`hOJQJ^J ^h`hOJQJ^J ^h`hOJQJ^J^8`8)^8`8) WW8Num1WW8Num2WW8Num3WW8Num5WW8Num6WW8Num7WW8Num8WW8Num11WW8Num13WW8Num15WW8Num20WW8Num22WW8Num23WW8Num24WW8Num25WW8Num26WW8Num28WW8Num29WW8Num30WW8Num32WW8Num34WW8Num35WW8Num36WW8Num37WW8Num38WW8Num39WW8Num40WW8Num43@PGTimes New Roman5Symbol3&ArialiLiberation SerifTimes New Roman3$ARIAL?4Courier New5Symbol9$FreeSansBh@HF@HF$5F!``!``'000DOC and Java: Project Requirements/SpecificationUniversity of ConnecticutSteven A. DemurjianDyK yK fhttp://www.javasoft.com/features/1997/nov/rmi.html DyK yK http://www.javasoft.com/products/jdk/1.2/docs/guide/idl/jidlUsingCORBA.htmlDyK yK http://www.javasoft.com/products/jdk/1.1/docs/guide/rmi/spec/rmi-objmodel.doc.htmlDyK yK zhttp://Adala.smith.cis.syr.edu/~hlwettac/cis700/Compare.htmlDyK yK Vhttp://olympus.cs.ucdavis.edu/dos/iip.htmlDyK yK nhttp://www.javasoft.com/marketing/colateral/rmi_ds.htmDyK yK dhttp://www.cariboulake.com/techinfo/rmi_corba.htmDyK yK >http://www.whatis.com/iiop.htmDyK yK http://java.sun.com/products/javaspaces/whitepapers/jspaper.pdfDyK yK http://java.sun.com/products/javaspaces/whitepapers/rmipaper.pdfDyK yK http://java.sun.com/products/javaspaces/whitepapers/dcpaper.pdfDyK yK phttp://java.sun.com/products/javaspaces/faqs/jsfaq.htmlDyK yK rhttp://java.sun.com/products/javaspaces/faqs/rmifaq.htmlDyK yK jhttp://java.sun.com/products/javaspaces/specs/js.pdfDyK yK http://java.sun.com/products/javaspaces/casestudies/allamerica.pdfDyK yK ~http://java.sun.com/products/javaspaces/datasheets/jssheet.pdfDyK yK http://java.sun.com/products/javaspaces/datasheets/rmisheet.pdfDyK yK ~http://java.sun.com/products/javaspaces/datasheets/dcsheet.pdfDyK yK .http://www.ucc.ie/xml/DyK yK Vhttp://www.w3.org/TR/1998/REC-xml-19980210DyK yK Bhttp://www.w3.org/TR/REC-MathML/DyK yK >http://www.w3.org/TR/REC-smil/DyK yK Lhttp://www.w3.org/TR/REC-DOM-Level-1/DyK yK :http://www.w3.org/TR/WD-xsl/DyK yK Xhttp://www.w3.org/TR/1998/WD-xlink-19980303DyK yK Jhttp://java.sun.com/xml/ncfocus.htmlDyK yK Jhttp://www.jxml.com/mdsax/index.htmlDyK yK Nhttp://www.alphaworks.ibm.com/tech/bmlDyK yK 2http://www.javasoft.com/DyK yK fhttp://www.javasoft.com/features/1999/04/jdbc.htmlDyK yK http://shrike.depaul.edu/~iilyas/ds520/enterpise_data_acess.htmDyK yK .http://www.oracle.com/DyK yK *http://www.odmg.org/DyK yK *http://www.poet.com/DyK yK :http://www.objectmatter.com/DyK yK ^http://www.quoininc.com/quoininc/dist_com.htmlDyK yK <http://www.acl.lanl.gov/CORBADyK yK <http://www.acl.lanl.gov/CORBA Dd%  `  <A?b jOEH8 n jOEH8PNG  IHDRhPgAMAPLTEU$$U$$IIUIImmUmmUUUU$$U$$$$$$U$$$$I$I$UI$I$m$m$Um$m$$$U$$$$U$$$$U$$$$U$$IIUII$I$IU$I$IIIIIUIIIImImIUmImIIIUIIIIUIIIIUIIIIUIImmUmm$m$mU$m$mImImUImImmmmmUmmmmmmUmmmmUmmmmUmmmmUmmU$$U$$IIUIImmUmmUUےےUےےUU$$U$$IIUIImmUmmUU۶۶U۶۶UU۪$$U$۪$IIUI۪ImmUm۪mU۪U۪U۪U۪U$$U$$IIUIImmUmmUUUU + pHYs| 9IDATx흋 }\&KɊg2bК>\& .9h#9h#9h#mǿufMtrKȇwfԯ&RnB~-h Լp'ql@t9=_iW^Ǧ=oRACB#}E)X[@! єr3P?Wqe:h)0ؒStAVƄ ?+)|·z5q3kйF'T\yxBu$xhseqz+SƹeErZ6!)K91?::3f逋 +2KptKÊ| c8\dVFo-᪵]Rs$p;e:9+,do} R@GIW=뭯&ZELfW瘿 Z2)@K%pvӒ/:;K6=YC@Afj:ĄA]RhYf_ڑ^3k>~twfަ] ] V͕3:6A+ Z]\,D2E>%9h2n z)hëM@oCQslb7PFm~ I=iO=O*8A@~F'Wp7h y"z`:'`$8'*@ \0JGajJe5}VU~8~o†P1.WFet5hFq!Fwc,z`5Ѥ 5?λRro(qw`MzN)io27 w~^oZw-,e{Ewo $0e+~6c9FEUA0zʂX/5[6!п7_ E ]7 UWF!! +PjЭ!t, s+rY4@7聁цH7x05gF"@]YС˪ϗBU>ŠS ;Alj4uQ$0gPIkTN;De0dWX4| Hہ PtUt9="/H7e=/ݙsk]tz \j*N;;?4\*Џ{5M/ K!ct-h&@CZ4b֗v@@yȗz[@a:4G| "YJwVkAsQ*!'mLk@ɷ)IjAfEr ZTB+~"[_@b$c֌/^y<}}3:}al&mqӻApZ_>:fo@H@tUN Ё2b8%GVajmr-й6i!j>s@\-2r`=MoL<tȿb` ԅY R=heS'뫏04 :YjCϮ+.A}+fаSZ>izаIZi,g@ߝ=F}cZ 4ֿܑ }Z o4XnZSii`֏*?Z㥠MAGNjQ;z-k @Jh]Z? n 1_Aw5Ljuēi]P>~M|o B4ھeG)!m%htP3ׂdd[GHW&A\#AFOoTtR [|m2$j5l)irпwy/u uJtoҁ Z̘]GlU#uI|d[AC P!ES|N;D7D  ͓1Khqg]9泙%hR9{ I:^PS\B)P:3h4e 0h,@߅)B#)X . XKhr SFQ LC0[h.)L#(X` `!oх)N)X` `)!SR)P(XQlASP)PC(SVE.+(ȖS1,b XL &Sp9_$ Wج쳳g&a7o즿_)HJS(|ŲJ$ dBKDuS&P B:v)HZ)UApa x lR A, d bTP0 k1 Π*L`X UMKr/$S= 0[ig5Ap}Syd 6T!(ÛuCK l/i#)]PI[ʙ{ &`We_QA#)DI,[ dK~[V\IQp9.uYQEqˊ)1 .JK|xZJ)qK{oܝ.흂38)Q?]`P;1k t=tO6Ja1!(H:c [Ǹ_ Q}NG-_{{<(^)=vB \ys {qA X.EY]*67GAuo=eHAe*6(lpI)+Rd8i^ = .=<(jSd]`yyRA%a)8!͂vAʺ%`ix :|.[Py3%ɮR`cj<'P;hjCp:&b):Z0'ES` zkCS9~ZunQGگkS}RܢF1P?zSHz|tg V3=w8d V`ߎ)(8}133UB:v+R0(")S`{Sl= S`})SР`N6=UW)QG)ߤ@ˊ`9D=lQRR6`>._yꂴ13`z5 = Җ:}B; MuST(;E=_ӻnU|A0𾞍$IԐ±a쟂:Vh%ڷZٺ@cYS@;@zd.`:o[ ) Xn6K+TvcɀT:yOi+Lx\ b>)SS"+`s26~v6?? =~`q7@W8A LC29(%@~T`j@=P,[J` F < N5à9zrLLP({BM2p# Z< ,E-`T݇nC!I (/ϡ?W?#`B ֯Rp IE ?"9̱E@U}ܦi` *6,>v{Hs-&Q`,]o8LpQ$<@cͺ>6F$hp+TJEdA057aX (0EJ"S0T(1QAݢ6 S/ p\mI+)k) /Cg Q7`O d D[a27(y q: +cj&a.b)A+bCJMSPwEgpX,U(!)mR - S r1 pH0Jgpr4}X(pi,J< 5 {fj3ɂ+J.T[{1 (xx+ h- e &{|OD S{ N xk0 /P(<-I^$R 1dLe!E !+@6)5 )puPV)wkBX"@zXp%95 "=(x" %tP@?ru,.X՗ l`1-v`MR\ I5_yΠ. Uujc-2bj5.MDSa0'[ҵ8 tos@@U*cUKk)x?T^S^*VlȠ.b5I4 Sh Wv]o9)v$},FY9KD-pu,8ʨ^PnѶYM`Lz*-,MCι2u},vs=KhFy%84P(!B,[ z`4e$qH /PB(/@f Fh@44Nʉjڇ 1k; :xa!b o7bC[>y'SPipHP*]v9ȝ<޵Rҍh)pu SPP ɷMnbKAZ@ɗE~"q [<.6 THlr3L _&WBR8D6(pr7r7JA2%}P@V(p3LQ 1Q:PA ԓ9n`6) )\ȉ|C44#c[3#$)`~At/+30zB,@iGhCOb eL%LN)N tg"MDR1?߿袇pFQ5Ks8 m+իXyS;{ɔ([|EMT''Z ҴT{{ R^wQ.@hBm'$ۂGO>ƫS7|`>[(8oiAp 4(Xf}O%]6 zUs$$JA8 riIA눱ʍ" BXnLP0*ˌa.n ڶ]@!Ǯ >`" d|ɚo}uPs%"!_“5 &RvSP~_ݭ/lA-MZ)]@d=5WBX}|\ RJ5H&Y V9 =HRP?UIȰ MsbS[[Ҕ=ŚuI d>LiLYs=׾)֧ \Ńm1&a~)hBː@1/[9@<{GN! )v֠@<R!8W-rפ`]񚶎m"9JF٠!A4k%αOrA9\DˑU)XF)6r-]^\S4׊P9EIkDJ|XI9uu6xAl\qgFL)d"aEJ)t*qPDa4FA8OzxdAMIP tD:NƬeI[CC&SjJj"AS'b,}(@+Z߆Nu OrPSB82` @xbP[BU (ps:M` !{oUHMf-M]9STq Y(x8|O9)5 L`V D3 f0>堦)XLxW:ߑY(KwkO9(8!PJX7M 7FAQM6 dd(a 6QP,UO+ k1(bAP0Н|k8hr; 1Qqx )85 9(x ^┃n\l(2emof,BBX#.lvJO 򢅧--" )WtHpG_ INĝK0Vf:y5X@j}Q5Ɲ\i#Tsl0j-B޿-Lc(j.b+JÛ:No)d2ם\ qw^$ - k0;m6"TD-ha@mM@0(n%+Z:WP"vr$fF 72] ( 㺴. |Fc[ũqa7@YG(g5,@J$X4甃^^(kۢ/nՍ2.ESR`=i>  CS0Ƽe=;[W=ȡT!(Lnj7y"I&j.)ՠkonA VCRZbl4Φ0r-l!h1-]`N-gnrjPBPt2 ЭnPPwZs9lD TIz˴T[>d@)Fd B)hKD"h\0:.c[V]F!SPu )~3+:Cg1Tw}S_;IDAT2SNw=cJN䊦وLA]UMZQ'c"2)UO T4QL$PmD TXw2S*W Ɣ48R|qNf BQUDvUGوLA6 ]h_uL^ <3_raӵ mD TWR068*j#2Z)hO\i ,@/lM9` BA#Pm0НjJ Ɔg\SlD T+iz ^f?)5 l$SP3PDu'@aAQ@ i&s[? @NwvŜj=^MCםkf3P` \lI+z ƈ;i" )( w.`ҢO{-d$*g^gpa8)yĠ 씂b 8%Oޅ1@ٿq<ʊ"ÎK D 6!n^)z|n:2ݔ y,{ h8L7j1votT/-3ZdϥSP>sM)U SS#FA#vgLNGf?1/ H9qUj=RЩoZ0MaW(H9X~Y4(0e{D-6{D]PSy)mF S]j}\J#X 웂<.}`ڦ5 Sk JAa!RNpD7` gzqyd [L)`ܹx5Hsiܪ}ob T&mt~J]zxV[u0C[~_%9E=)8r4f_RXS|RӠg_)R5f־HoKFnj(i. Ե叮#ȯ^dۯ~n?;?cCVsͳ׽ڐRU[OE([G@mb؟wP,:DFK:i?y)M.mu53~)#~ږe"]F!p6Vj\M=;rnT=Y}`UMq7/W>{o:4޽Ys{`wkSl-/źOUϲ2C>BB_7YIl'i!K8|0t]` ;z!7n~r1%FfSZ7K[7@C|"2oa9-bq˒8![]?ۤjt3mGgJc[e,&L}5Ȅ8 ;0j|C׎5?=;6 (/* gaT(>-2" mn;zb:F;cPQ CykjaDShE˲",JErwocH}E!}Qq.u@E(Fрx{'Z K|p5o]5i}e6ތQ1F-0u}&4mG8v -s쿷1ozGF=D~L׶/7SV¨ѴK -=0!RVp^nm;Hrh3:[v})?L,F4W\}{u SF5vDalM/,og8[Xu̬6r°i)OV9.ؔ9ZU%WeߑooKݜǾ|Ϛ'YUo TZ>Ԍ9w xE7_ӆ'bSUOX!^z^V&_9,Ri*e`:_rnqYׅ쫔 V)9D.LfN[7+ܰU(r4ߓ4ntk-$ل[Mvªy+{btjNK3BЭc{=$}.g.cP%MϾ*?=tVyW87'knF:)o7iRJ)#e髲uxQzA/lOM˅9HyM릀Yxv#1i/1虨Ѻȗ/>p*s68dY2LL- Z3f6ȯ3/RAu"08FN2ǯv)ܾȘ ֮V keɫ~= mq`Di8o"-֋я[:3qmg uɔu߹4DHRL^cNPI*aEluC7F`[]\j6?^hNɅa)[+^<{rrnR?''3$(+8KF/e*;bTJubu/3!3$DqCBhe/1.גb{ h`W\z#usKDo&w[vhU"frw$V+Rю$fxg[Í)$0=*>eFtd#dulѪcL}=["'s3;.ƛѶ/ǟn 2tGljiw4ݩ +>;kj=c`߿ 4*|=A BA*YmD3QɎHͤjy) qYءtڡg3[Lf:ooHlk\o5*9JP8'cXQ kiyw]ӭEIxe(.4NjO펎?o>g,cg(Ǵg-Da4~[9MrEr*sq" ~]5z?b3V1iӞZfKc4Fz誚Y|j՘͎Ӟ>vO3nȣ_ݗxp02!ǿ,8ӿkf}L?cG ֯w>ۿ:|뇿y/2W{k_M.oÿ\L*?}U_hj:yO'^0~DG[.YL;A$=i KtĀIpQbH^iteo3g7E2+m)<?Sx*@y(lǨ`?O/ީ[/W Sp"0xd6LQD#u&iھWZQz EgcU6hEnp7&8hBtk8Jmf  }(C~DoAHjڭ \WEh+z`*]ښ6w2% tsٗs7\f%7 ?h9QyQyD$d)q{TQ힗Am~FwO\_*rz@u~.ˍSy=)鍈Pm~Fmܤ\S"q}kvwSe'nzq-=.֥GJP_Kס`(t$IZFO:NKF R*dɪO3YR3S8#@󜈤 ?{gH9 8s$,Y҇8C{v BzPۇ.6Is * āiQ;Hb VI 6LSiR4)aDnCR~Gb5$h*CV*ޫzyn\mC:fkrq0} _. Pc]sVmpd:v{'avXOÅ՟G 0+ߞy5 d˽_G  |Sz>Y ެ#asVά]`5{Fb/~d$`ǝ/skاT&Rnx$bStfgC\_ٛض^h)ulYq]pcUw?~TS tQs|T68DT5#UQ"Z|_͔xY[=kwÔ;rN_r%+?iN2U!P&X{jNT S*`业MM fLZqE+;f?Ipdc|csOi| J9.ʴ 3=01T B!0L@ z db;Us4ʛiCݺiW7<\bd6-`¶X@yQ$+^#SJ^_Ra]cBtP'ډfc""r'HLi$k(?rW`Z[Hk鵠>0zkY]eNFu/Hٟ 5oLAk~^,y__I{k .r;8欌۸9̶ ׀?ǮI.`x]o+;6o^7ꚳ2n4 Jc"J$(FJr/%RDP̿<% zp&EEr8cv;\5gƒ,\/pX#Nw@'6e9@|e  Ufa1Xwuө'zXֶk=qPO!iFD-FN$fU"`k6&|ڮn2ntOy LP'ϑ<9:ߘ'(htO}3w+xd7 Ǧs[ɤ tAwsi8%jeOD IfS S6Mq>яP*ВHj4K_&{ϸ)FrPʋ8*lNb/Q/S֖}qÂ)\%ؼv\g9C%vcFY`ӏ'%(A_$ܴpD*aU2")l&?b\5NVCi'߼f.otFs|"ͣ.Nj6fw`} +߷k}? wm 2*{yEvlw Ћ6ak`:ld[3 Dh0'(\w\故vaۅ/_܍2 ޘА^JDD%fcj6x3.;q"`WsWm`_zSu`S~ ϙa,uߘ "ݔ&Rqr/h86ӥ*&%Wɪ`u=xLp q)lT]ӯX⪸ML%+_S]+X)jXWS)+lZQ*_ͫTJ, 3z@F3Uԡ3]qԝF3eQԙϜPW _m+\G ^F肨 /wV_437wnLMCRں94437Fk4OMC?sЯLQ/Toiaő͛sJJՁ : *L9ܓ<@`n.zi.o<s\DmG<|' +蕦XG<M=p(QEiJd?Q:̿T)`[g|k҄H~ʂIbP" 9% jxTrQ$i )IХA]|Q U38j)Z{m&pwϢC[S!'p͜;{;oMvw؅wz}7a`7So[vam87^&;~>ʸCb}39^mx'۔ע]|;pH @Wv \[QcIXͅ,˗pE-.n\XŎu/;_VO1=(v ;X2 ~҇iOV_Ým;h,/9|a+ kz+Dcُ[=ǯPF$$i XYi(iE Z.fIlVMJ3`Kmq[3Z N~2I`eCĬ>/s zٰpPfLE"Ae.agHv,kqNːߚCᠴm0XU)aobեw.9c[q$z3рL󣩘?S||FʼnF=| 1? Qt(6S^UB0pM=(c(Nt?Nqr)ȝX/9‰4LNyC]oJW~DaxM䋑Olihǝ2FMQ9~UN˷We*:IDAT}dܥnc}IZ+]I*>TޟpEDZ;9N@kZVlcԉ样us{=)Z |kFL<~mWFkc"3Dֵˢ_437 MC?scM5:&h؟1!と.4bgθ1 ̍y3ńPͧk~D6RQ_U:W\^"/~AC?ss)wK gX`DxxDH%nѼXTiρpɀJ jOQd#0*p ɡ#2yf8'\j>xhiH9k /D>rPؘdl"H/$q Yu*2ȄAUzgRRe,M+%oo"}\m+O@+[kAǵ}@nW}ht8=J!?e $ LnٓC"wjGQE69 Ȗ)9,F haxzh=?N8Ql&fQ:Fh(ESQ"9" )-).S"N$'QH{>A4~JG 2Ѽ3/1YD{[S73|^[`kmYF6kvrC60 %lVGGad[ 8 rw[۳l鴏ٮ ߚd>ϣ]puhd+gperH_H#قȃ {0؋garI @-eB5̅l{ef0 3; =hm03b i&iLAR>R>$M*)wΩRuN:3*̆sO;zލvE ܳ "pr3vȻ]b뜵R_ OM@9P`lRG0> נ4.Gt ȁN(ʄ,xk~%e\Yv)yXrL~0^_sOK.WuE~]JiZH61bY!jKIyUD$' Ov9[\ ܆='۞{"P(LP_ (\x)Uxp)}ƿxy;h[u.sSܕ7jʬ{?10u&ܷP1aln-0bs{p FXl ۹& թN;Jszrg]UKlS-Sg}[@Y9.kGhO.![鲺YsFDx2Ւdϐ\i?R2v о)!R)lɡlаJU? 7 h} _ XXT + @*E~dʼn.KYhr8 {ޗF-Y&&eru<8X0auy]-"U(HgCqLw2Aѥ-֨;Ϭ:< 2v$yxB܄yh$ )묭)p6~NtZ >`A[;^Z2u5Fß%I$`] HXѥRBynp @6z{_ll (@` $;(.fwC)VlwySź @<@[S: H%JJ"UyHTC,rD%Tz_[a[gF7gC/)Ux @EtG馧#0[Z?.wSSce)K{JH',O&v;Gʾ}nat>@6})y5mTqMG@I;guӟKع/b>klLglLglLglZոϤZLglLglLglLglLglLglLglLglZ3oWIk3ӟ1ӟ1ӟ1ӟ1ӟ1ӟ?\ mW+r7 6~4\.4\.ϠH۫hh=3A#2g$Fg5ϟQ !SOF0kuQo-mj \Fei4rr[*3QZ`d4_lL4Fk M@ciﯹ y}5u? ^{u? ^{;6؆u`Z˞(W{`];}cgs|Ns9)̙ᯥ&Vm@AEp5EKi46vgmpۅШzVIڊT ΗIr|+z1{evw) Ӌ*f"\7;ct ػ;w7Ҍd+D=/c]靝Jkkkc9YRy\*@PR @FHҩXY'<ITP5PJ"O]TI}6@#߼a ɤ$Cb>|Z"J$U1Tb>(.-DHzT꯭U:MD3Ggw!m"}*BiZJ-pm2` ɇ+5xƖ =%SK& |#pD}=˦t&Ϭ 5 [1ՂNT'?t[mߔ}#UaqTLݙ{ÅQXɖH#ՃY~d!҆w-`QmgC`ZSv~G8Թ $T-4_TvFNKО:;d82OA{!hV <3Lk<6|Տρ(Gֈg(yqc~@`y{Ηw&*R7=.4a -P";,x8xIBOI\EOxnD?&4PW8 A5 SBSӬQF đɃzRvtUxS;u{r=q\t|[ OXܝP@]nEQmXS^{& Pj6j:PI)W|t#$ ʩVЎ7}OhYqq[ vcޅw5<6cl=H\J ǟ `+%6`!e@8G}C$f<'axAAi3}a: 5!+Ы_ Y=Ro"9A%_+׶w{RWt%2 %ѭ5\I ύey DNI…Y!DGq 31H/ϟʪw#) }ro<-To$C}l`ړJ•Cq}wA^\{d }/7*=&K9Xl1?[.OcH3Ƙؔ7T_JsID|WC 8=_g{[6'g>?{Fо <]χ?7Ou}@iRϟ1VRt}v2p! 3liR:HFT !?;趤~[̍)_+]SZ浤E\ؘؘؘؘؘؘؘؘQKּ sKIENDB`DdA |  f  BA?b hZAVB4 n hZAVB4PNG  IHDREPLTEU$$U$$IIUIImmUmmUUU۪U$$U$$$$$$U$$$$$I$IU$I$I$m$mU$m$m$$U$$$$U$$$$U$۪$$$U$$IIUIII$I$UI$I$IIIIUIIIIImImUImImIIUIIIIUIIIIUI۪IIIUIImmUmmm$m$Um$m$mImIUmImImmmmUmmmmmmUmmmmUmmmmUm۪mmmUmmU$$U$$IIUIImmUmmUUU۪UU$$U$$IIUIImmUmmUUU۪UU$$U$$IIUIImmUmmےےUےے۶۶U۶۶U۪UU$$U$$IIUIImmUmmUUU۪Un.bKGDH XIDATx]( t1G1S *;qM1 tMai>]wJ9rGKï #( wVq~r3' /f^vf'r=YϲcP -_arg륏Kh):zh3|3zr薖#;৕iO䄑!5,dQr;Sò@ P_9<>f{=hw[ -i6:^- t;*\Y%g5WX%I|Y cK w~9.W02#C˻!m l(eaVlx~矝ėK[fBY;O < 0aFbI s9/$WDCxQܟfO񭽂Y(_EHg||6W;J.+JAgPJJ%`sN(EˈRT'YJͰirRE)'\^rRE)'\^rRE)'\^rRE)'\^rRD{wŅ `v. e)- ~ܤb5"Q6އC7-DnSސGCC0[KgsL>,AfIY pˁ~R@ md9I b^=Yק]J\~$GM;,}}J\z}83Kgn#^7`-0):ÛBΆZJDc ;C.:NJ/ M15nO_Z!muyiV!hJGu0rx6b@5:}zbGCL+]㋎2S#Z|݀WvMܞ3?`pG!t3Ĵ6Q0u0S8=Pe (ECק*v,닑.XP9& ;H$[ {m[[Anyw. v8F90dBC+lE!5+J/}Pн|of4qy#GgL^S+:ZbZUi u@%-J$ #tv0|qcSnCe\[ԻjtFPL~{!E,J9 c$,&W;Gu<%ޯAhɅBnt т(o:v6 :0#9  G S;8>(VjkVQ MF$Pf9(^ѓ:#'ofCqr@v+F\kPHc0u's5ilQ/udmzK*xR%ԕu2-Ȱ bŭ]E1aV< ;;Sj%LE[TPX1&5j\4pRQl[Va #.m䔉w0s{`-{=C?; ;?)W<vAdbxbiF g9eZbi(KFj]yY{LP,KEfh91Z45'bO8w3-r?keAL}TO7ذ rc [ovYV#0-,sGiKnDZm7oa!.$h%!vڰ!xGѫ&k9e8\;~!o[0h k3󃜲7v6>4}rV4J9򢔓J./J9򢔓J./J9򢔓J./J9򢔓J./J9򢔓J./J9򢔓J./J9򢔓J./J9򢔓J./J9򢔓J./J9򢔓%7OiYz5J.лgK*/%K:j%w]% v%ڏW2;47<攖–bc6T03ukhσ4octxҤ^RMc9VB"B*o<)bD 37x4cO4! k O"r?>ҊizM/vͰqs \$Ꭱ^"q޳2y q竘ܓ5%?^:&נQ$C!52*W5\I]HkiDȦlCkCv`[H*7Tw1׊!i=Y"m(гަ+d6[Z랩)[ tJ }.Q}Q3y.rdt)kfyɉvHDcQ!cfDEN-8F;5q2vΈ ~aLqPzwezy^rA c,FXˤRd q N\dzz1/79 S|fܐ1jt-9xd iWN42Ix9hGXkY+72񌇓>ɡ+LܯCH{AE۵/|#.JȂF]luc2}vZ ]}>٭vb6]/=O4PjHݶ F.*M]No!RR}Tr*ܷO]ꔺIENDB`Dd%E   f  BA?bF 5Ca44"n 5Ca44PNG  IHDRk4@hPLTEU$$U$$IIUIImmUmmUUU۪U$$U$$$$$$U$$$$$I$IU$I$I$m$mU$m$m$$U$$$$U$$$$U$۪$$$U$$IIUIII$I$UI$I$IIIIUIIIIImImUImImIIUIIIIUIIIIUI۪IIIUIImmUmmm$m$Um$m$mImIUmImImmmmUmmmmmmUmmmmUmmmmUm۪mmmUmmU$$U$$IIUIImmUmmUUU۪UU$$U$$IIUIImmUmmUUU۪UU$$U$$IIUIImmUmmےےUےے۶۶U۶۶U۪UU$$U$$IIUIImmUmmUUU۪Un.bKGDHIDATx] u08`p.2t.0KJes[k!.1$(UBs!Tr|xml%Y 8".̜e+˚7]-1ll4DAİ3Q߼}(Ȕ Ze8#J%KbXh R5U:r)X: Nkp1$ȇH0hevAs@Fp Bџk纘c,Ŏ(AHK*`F>r%vuJKrبPhnVHk6&,K#$rE:*pȾOI{!YQ^*(Č(G1X# Su ɉB̈"nAkWll!YQQq-ECL@dhTR;(YcU!j #`J.K#se 9b ⪅a9DqĂ SdcAX)qgq2>cɌgE}&<4V3 r|\BÎad|\lxO1u>TrMCxTr|\C:*P·u>Tr|\C:*_Fgܓ[lj1 j%9)ܡS'ߴ0m&urPMֱ>ᢑҜZlilq?1 Ikoڣc&'! -@iҶ&Na:%5E9%=Vݻbx(v5`s8娇f20"wtetKn’og KP#;nVs#xZ[ :@>?6?ƒP5XHq`c1Z`7&V}(54ɏ<`z6X q=څ&?$/BB!T3xmn$3"1xF_׹~ o(l*5b-䲿CUeRcnoW瓪h%Mn;Gob<;\#"k3l= 6ޘY4JK^b)`f;&e-쐔5 r8)Sro_eӘkvR^"p5RJ?/ǩ7%eAI%s!ڮ:)#ףT7}ZGM40 L1ߎȜF}{Ꝣor 627> > P}/<x`qaD4rly"$>Ƭ\'MRՈi|xTr|\C:*P·u>Tr|\C:*י.{Q<-*P·uFl&qϰru>T3u6TrwxO_Qa T˴joL,mZv*݀d1^`ږ]fx]@ӳpz]˂7 mes}ͺlK$?0qrmX/!*{Kk lcvU4W ~6O|)5\_%af b\qFV:\bɎDN Dzk$[&HRJ~*,cb8Y n64erS2m 0oU`ZhʩfIr<{ָfx53U> $1tgLpa{ 1/kI|Ow$Ӏva,HS:]Ӌs-Cy_p'+ݱ4\ح [ϵe-<mCT`v}ȴ|ky7RtYE }Gt4 2)&aAG& t”,'?k=nh֑Lp(,I N>#_cMF.5"5yA47fUÅ|&p?X0S0u*H̶ ,‘B[r\\{ԡ$S-ċ`C`*al%ݒ>A2Rp?y&y}E~ow ǻ~ r9 ݴ 7SKzq}4\g=d!KI>n:4fjduJrǎ : HusƄoRPL%1-Yxx`WbsرuRs\r\ǎWՖs|E^hFS~LcEErz3 φyaìqchjͫ Ҵ_;J4TF&A"6$UӀdO[M_[GXV[6ThrE"ThrO_cj#e^MKMkoP[}_1|q+GE"wΖ;T`ܗ{dۚ."_qcF.u값c$8uӷ`VtajL)Iu77K'oZe.T$t/B9kze!+Je3%A*`) dWizc&6v*Ұ(7Z%_p)QWP jJr ;O`)k^ΠR0>L7۩Di(  m`tCZ۵2X3*mnQ%D3d{vH| I*B脪*~*XI0/sZ,tGmi:C⁋,g)*^XrO_cj"Q^}Y\!X7SKg-@Ij xy˖R%G‘j4WuF-zMD'SEOza/ٳ+'j}``zsr Ep| YVyͣo^~8J{x;CU'* \\[ExE{c_xLnWrU/VЛr)siczC;vEҋ9q3}Xg'_7}8״e[sc4ExCcI mIll*kx WWt8ќָ t"s$JѰ Ł|7uJܱa0~a 6C6]~zN5΃{#[yff{ct,S,:~X.RGO:qoC5-0JPC3Cw 3>2f0 0~,wEk\+;JܥZ&jJ;333sCծq Z Qeo8w;*s uRv Zu]W7{<חV0".Aadz΂6uIr^]9&\>$|jQi n ]Ur~oږLsV1Aqx ߮i3÷~vq(?bNwL pRPS D"w%9S}]6Bwv^jtsu10ޣHuuRs\r\!/ \.-Yhu'\fXr e DBvIA~)F \r;NDvT~Fɸ{զCo9McGVܫ%Os4/s}kwr}R+Tx{N\: rL~cbK|vkf\]ֵz&Uz}(kgy,g6n6X\(Č 9P9"FY֬'l,k2E%1"0bWw>UG3^;*E\citUXĀ.&x+?6GiBi(RP$PmlY^w'oad"\:)띵EbbBv'Q fu zRO;BzhjFlsEIszu.!5ף(˟blkyJD$/Vy`Y29? e٭45ŁKHƤUFSsvZsklaRl:RTol1 C;V ע`b{H8ec4isB\ף Zf#M<%z'vVd-PӱKW~6~}z\k!Ha?(m.{\ksU܍45m5+vN![ǒ]dn@H:r=A:`]ȣU%.GJvCŮGjRc]G(c.W(rpjIcv+ 4ioL,QGpPU;4gp1kq#(<-J7~Oqu>T!TnjC:*xr+l.;]Pl.<5P삾[8gXE:#=V3ܡr͛O!fD?Cy_2bMmx{y5'c gds,!<|x!<`zƓl}:*P·u>͵y1}(~3wYcͲz# !hAVHC߃f+ڌ*Κr$eFVheD~t Z#AON\ 4^Xۃ>(0!?1egA֦͵a/ċ}` +Fٲi<^wB\KR (Rh0PKt(S&!+m]]71ZRzbݣg$uvJ?F)'}XJѠT@Xד'Ȏ6 n3|B\Zp0]n(n,~ esor|\C:*P·iQ$IENDB`9 Dd_<):"f  BA?2 ߃"OV5"%( [ p!S ߃"OV5"%( ߃"OV5"%( )T@ GPk xZ{lݙ}6.bcb;-&n z4\7Uզ̝swإDZn@$Bp"'QҖ6!mL,Hb%(24tfvsxvg^9N ^54# MrWL_耎`" `2 =ׂ%I_Vu6̨99ZFŃ=$EO_ӻy<}*YoKLwtQJJE>KI6@cA~v=ZY-g 23*d(x&D)kFܴ(_v7~)1OAZ} 9}?' mIVYflzF|f;el0MFh&XjzM/jRFo$iƖX|d`/!5RȞ"a&=f_tvv5Y(hk0gl;{iݙz(]'{jb-FI.23Y11EZj[C83RqHQM4iGIbfUV3@| BH;4LFTm:Oc 5[Jc]lΈ<[-]ƌ[k4 /svܼ;~n\-8P~>A Vx̏-[#c[؝4-CE|L WpxjUaq|J R+&}[#~dȋGRٵPz^#GI~:*~.Q4ly*5c= |Y >.<\a@_+2W]| ^q< |߄c؇Na< F(XE:z@_uh.n@ltFamj Wݣ)H@hwZՐD6 rV<J,%i&{-J"[¶QM1J>V%+w&rW_g7Fw#+N\HVV'$x]YNtxx{At/zЅKx^]X`Is{+ׯǔ#0 um-;O*ZG3':fj0bt'Ԋe_#D_ +S֊W(:tbHi.\lN%+waUê;wCj3L!՝;7n_# %hMܲ%4k;!EqʃQ0\UOˠ`@!׎2v\Ecy߼5f|s:pr]$Y)H Jv2#-ːGSi6l%!6mr1K1(@TŘBG :u2Ϲgw\^P&W3Mh~hI${#}I#12T;DL^c]9GqoE[=]9Z ڒ;x|*vq.DS…;ԥr03yEr4OƅR9\8Ռg<\xRpFKTObR_/ ;$؁gt ѯ_WH뎤|'Lmu?+j翯q8]b5뢕ȓ_Ӯ^\: ]zqwh忏_ IcJXV԰SCRwQZy|\ZwbH9+KV/޸ ǥa՝!&tC;w\U;"F}"e>ɟ8S&]&>X-LZrR>#IRV`)mԳv{o!Tvw2YfRەd5,uDe~N_UŹmcӺyko満uZ0)Im&A=xbX˦Va{ΉSI#;h2L#s,YUHȎvR<<6X,% ?^$р $t!.uD -?MMIS)ĶW(gI}Zp Z= ':VCy2#F#8{I-17F4%/ѥt[ɑ߿ˀ2\8BD]?]eULlY.t`PP&8tJ"ZƖYq7^/Em)>`YȡBcJY(q7D;ԖqJ)Br˖} ｯaćS(=2 Jy՜L֘˂ByƚYT6hCw`fВ˲) t:~~~JYO|'87>)܎pOr7i&JX$/U_h(C$/? H^/P)m")>;a7DPQ0{%kk)0ýFJ(?g#BY8?4s{sdAHSB9⒀(24R>N9bQܸ*D[{)Qov٩TB2xƟ_kZ???~E+ (}˩π@'PF/ifJ~GJi ^޼{x͵cТMHK3(%K/#^SXվfuzC]CEq2"CWXϖ*Ċ|5I~??+QEog#+Jz]GYxx7H 叏-c$K:nOJ5|{"zMhX}";6̾k*^/)lD{|L$f+,JX9FWT~տLtz(QUd@ JHP(oԦC = "(v|)uvݟs9Zq AV(r {{pYaofp(qp;eKbmR߾\հs~$fc:{6h7U`4a8䆲ӹBcp,yDDXHNP" 8 !l+;4oK}||/B 9~ ^緛ʂן(y= pI{mAE4#(͆u4K} *NǏ|EUm(d̹~cEќ֫gVc :}n4 <,7ewdsDn~O[=ʼKuHB:*ݠdnqyrĥ6|֟M*M}Ѣ~NQ&+=ţ֨ۜH}xw%/.{iOҋ8+2 D*Fv5u(%ZIf}BU<@(UP|Ɏ!d:fe=돷<8xLmo7Wi?=1$B9zdU3]zJY27sM1kR[ dqz(cdDKb-}|Ug:m9fEh%#v'³;+ W3 YZ >Tǩ!U*e"'zVRx?8<8~~~/JXژ,nH F/VȰՓ>UvOn(Ctn Q"pCQW4ʥ,=,CS|fKs|;1SN^a7oNyo=!h"2jo1ى@qĎ'eY390N1ھXfL=;%2<*} !̳?%Xە5`FoQo c\>/fB A<M p`BBW*ek2A2%ۧR%YT2)o qWWWƃ1F4Opx',e9Mr[L6ԾEnbFBv4βŴfYDr D1n%F1Ρ|lO +ٳ(ͤvwB1KЅbӫg>i\![2>;R6З2| ae{™ >ȑ-( eWNJ˸w[ + M B—>s2~ʰ\t}}}͙-)XcrW̵7p)%,aac#Ffr`^=QBlmqzf};>??ڶQ,79zV:tdwÀ K{ʫ`%}!ޢF_nڔ(]ӨOM{ƈ+{ZN R>W?ryv(ιK]4*V<3%^:B#IigḼv7eJY5#[Dt! r;N",K7C\t֕nx Ѹh`Vk!CY> 1V1 1 `{ Z=zRV]UD8/t| <l$81{} e B&F @'l~?lDcz.&٧Rfz''āPѾGe MA|"]8Bz eB;1X#;F_VOfqr_f9fwhO.5Ղ:SMv3PsO܋d uvMhwWzW/gkeN_1ׅDvrw`PaU{o,ڶTsPQ\YxG^rS'XuByM-lMT{i ,ZHL W^}h˖?h_OfǍJw Nr1^=}J9솒=]].n3S,\B\f-*Q챋Z{6\l]^dЕ.VХ^l9u2̧xKNLam"]-`˩LP).pƱ󦨔q# n.L"%sk-eG\B.{%2%3*UWXODiZV;wv;~WYuTe^f`0d|Ud+V3p.eu}8 !y2{fsjGf $i_`*i_iWr>Ўn3Y,[vp_<F~Wi.kv@)̜\)S`yYv;K2֣dS'J7?'r=HgYfX=/Y6W?FjB2Mu) &Dk)ʲ۽،2Y ++ Ь_G;ArR9)}Љ@μ\\k_pMV|n:.3 Go ?;^=n%@n4h[`d2ԵJnJݩ,e/=VK_b?E|]gS[n`Pv/z|-=eDŽNɬA"ߦ ykxT6t',x0;D T@6݌=—2!*e`؇37(0)#_2+ʵb& V!! &er2d&,#/[dV˔ɽ(e64RZ2.##;cGCht3P!s2/9nvfR-sZV2,z_$'k+؎P]Kf)P80M%@hԗB7e@V7cܝ;=Or2nF[;VzJߝ!BڒMr//8㔁LҗO2n9yPZ{mX#P&s`t D .r Z2sV!\v2 T2O| VCKfer\&Pw1qEez7j^D!2pSd>Mq2p_dn]uB(w@c\d߰Dׁ5Ip=UV7t nl-5R*CYv-jCC;kkPE [tgvw#@ZNyBVR ~&NQ)?EL3q Pg(}q1qe#T͘k,?E!},a|b>Vw" e} ^g@;BP,{_q{_#_ v, o WMO LS;aF/>+}$r;B>3,W*WO] c~qh#>};K;qR~/Q1OӋW5|?=Tt~P!8׿VH-$qR={iW+-]%?,$ 9~KҸ\Z MwNJŖɩz 2l|-e|:nT#jxMh{kzʻ&r4cJH{iVpS+ekQ2C S0ӲC⬽֖`FּP{A?()ݛA&2Mó6FD?O>e9B.c앀cZrBvd-4]cܡѹp٫$ҋ`>/PLΊWfL}(o\?3&>grA"J@Tck4:֏YCӋ .J.=%푾Bm*2xZh_ CYTgJ>V5Lvs*e++2r98оJD(+]oӮH ,fmEܚ,Mxt 鳢W|WzDAtPѶϽ `( Y.ݹ9K7\jY*5r6cTO%7F dU`/ZT.pq|\xHwa?<dQ)=8P*^]B[/*WD[:D0PpFjpWb4F0M)J'70D٪}AJ\VDe8e,9_8p9)VoqʴP=V\M4.,8x._|uB9{[h*77R&Id/,2 3/i֖ B5\3hF@GkBkck0PvmmeYR`q(G$aZeotbh!+CZPt6C( 2B( 2B( 2B( 2 &J>IENDB`Steven A. Demurjian2@@J@q4@@  FMicrosoft Word Picture MSWordDocWord.Picture.89q  FMicrosoft Word Picture MSWordDocWord.Picture.89qM 0Caolan80 2PU   ZnlO=?2o?? NQbxSNy;$ *?.JH :LN  Java and Distributed Object Computing CSE298/300 Final report May 4, 1999 Wei Lin Xu Ma Walter McClure Chenzhong Wang Abstract While Java continues to evolve, its role in support of distributed object computing remains in a flux state. There are many different aspects of Java available to support distributed object computing, including its main features (JDBC, EJB, RMI, etc.) and its ties to DOC technologies such as CORBA. This report puts focus on Java support of distributed object computing, namely large-scale enterprise system that involve the interoperability of clients, servers, databases, COTS and legacy applications over heterogeneous platforms and networks. With evaluations on CORBA, EJB, XML and Java database technologies, this paper explores the development trend of Java technologies with respect to distributed object computing. 1. Introduction and Motivation Designing and deploying a truly distributed system is a daunting task for the most experienced group of software engineers. Interaction among various components of large-scale software systems over heterogeneous platforms and networks create complex challenges with which the architects must be able to resolve. Performance, interoperability, security, and robustness are a must for successful distributed computing. Technologies have been made available to create and implement distributed systems. Tools such as CORBA (Common Object Request Broker Architecture) and DCOM(Distributed Common Object Model) have offered solutions to build distributed systems, but both require implementations to instantiate distributed object computing. While the notion of distributed computing is not very new; building distributed architectures over heterogeneous systems proves to still be very complicated. Java will help to bring order to chaos in this aspect of computing. Since 1995 Java has emerged as a truly elegant language in many aspects of its implementation. The power of Java has been recognized over the past few years in its adaptation to the Internet, and large-scale client/server systems. The Java language by nature supports and promotes strong software engineering concepts and object oriented design features. Both of which will greatly empower the developer who designs and deploys a distributed architecture. Many features inherent in Java illustrate its affinity for distributed object computing. Distributed systems require heavy communication between different components and objects across the network. Networking and network communication in Java is much more straightforward than in previous languages such as C++. The approach to component-based development also enhances Java s attractiveness for developing distributed systems. Aspects of the language such as remote method invocation and extensions to the language through various API s and class libraries such as JDBC, and Enterprise JavaBeans to name a few supports distributed object computing. The buzzwords associated with Java when it first came out prove to be excellent qualities in the language when applied to developing distributed systems. The versatility of the Java language will provide an optimal tool for building and deploying objects across the enterprise. Research will illustrate how different aspects of the Java language will support and implement distributed applications, and where they will fit in: server components, communication components, object request brokers, networking, etc. 2. Overview In this paper multiple aspects of Java are investigated, as well as commercial products/components to determine how each aspect or component supports distributed object computing. Sections 3 to 6 are topics including CORBA, Enterprise JavaBeans, Java database and XML. These topics will encompass server side components, communication protocols, and middleware all relating to Java and its application to DOC. The last section is conclusions and future research. 3. Middleware and Distributed Architectures 1. Overview(RMI, JavaSpaces, CORBA) At the forefront of Java distributed object computing lie two distinct architectures, CORBA(Common Object Request Broker) and RMI(Remote Method Invocation). Each fully supports distributed computing across the enterprise but have significant differences in their approach. Supporting RMI is the RMI API included in Java 1.2. RMI is a 100% pure Java implementation of distributed computing, and can thus operate only in 100% pure Java environments, that is until the introduction of RMI over IIOP(Internet Inter-Orb Protocol). Currently RMI is implemented over the JRMP(Java Remote Method Protocol) and because it is focused on Java, there are significant advantages to this architecture. RMI can pass full objects as arguments and return values, objects can be shipped across the network without extra client code. Class implementations(behavior) can be moved across the network as well. JavaSpaces is a new architecture built on top of Java RMI. It represents a new approach to building and deploying distributed applications. It connects distributed objects differently than that of traditional method-call protocol infrastructures such as CORBA and RMI. This model incorporates new interfaces added on top of RMI; leases, transactions, and distributed events. All of which provide additional functionality to simplify building robust, scalable distributed applications. CORBA is another distributed model used to develop enterprise applications. CORBA objects have interfaces defined for them using an IDL(interface definition language) which provide other objects an interface with which to interact with the objects even if they are developed on different platforms.. Java support of CORBA includes an idltojava compiler, and Java IDL. Java IDL is an object request broker(ORB) provided with JDK 1.2. The ORB facilitates the client-server relationship between components and their objects. All communication between objects throughout the distributed system is facilitated by the ORB, this is what provides the transparency of CORBA. The ORB comprises all of the communication mechanisms needed to find and identify objects across the system, manage connections of the various components across the network, and monitor the delivery of data. 2. CORBA CORBA is implemented over IIOP. IIOP is a mapping of the General Inter-ORB protocol(GIOP). GIOP is a protocol by which all ORBs must adhere to in order to be CORBA 2.0 compliant. This assures that commercial ORBs will be able to interoperate with one another. New developments in RMI will include its implementation over IIOP. This will allow RMI systems to communicate with other objects over the network which are not Java objects. While currently CORBA only supports the passing of objects by reference, this will support objects by value. CORBA is middleware which facilitates the communication, interaction, and instantiation of distributed objects across the enterprise. CORBA objects can be implemented in various programming languages. CORBA maps particularly well to Java due to architectural similarities. Thus the infrastructure of the technology will be discussed. Interfaces defined with IDL allow CORBA objects to interoperate across the enterprise. Compiled IDL code creates client stubs and server skeletons which map the language independent IDL interface to language specific implementations of those interfaces. IDL allows interface inheritance, another reason why Java is a good choice to implement CORBA objects. As explained previously, the ORB provides all of the bookkeeping work in the system thus granting CORBA its transparency when clients are accessing distributed objects. The ORB communicates with the objects across the system by handling requests from objects, and invoking those requests on other objects. When requests are made, and responses are returned, the ORB facilitates the following. The ORB finds the object being referenced. The client has no knowledge of where other objects exist, and it is up to the ORB to locate a referenced object. The client has no prior knowledge of the type of component it is attempting to communicate with. The ORB ensures a particular object s implementation is managed correctly. The ORB also guarantees that the object being referenced will perform the operation requested.[51] Parameters sent to objects, and return values sent back are put into a special form for transfer over the wire. The process of packing and unpacking parameters for traveling across the network is known as marshaling. Included in the CORBA standard is a number of object adapters. Object adapters interface a component s implementation with its ORB. Object adapters render a common set of operations for accessing an ORB and its methods. The object adapters connect CORBA objects and the ORB itself. The adapter maps the interface of a called object to the expected interface of the client. Object adapters allow components to invoke methods on other objects without specifically knowing the objects interface. This provides another level of transparency when working with objects, and also ensures to keep the ORB component as simple as possible. Object adapters register CORBA objects and create object references to those objects. They also activate objects if a request has been made and an object is currently inactive. To create true enterprise-class distributed applications CORBA requires significant added functionality. The OMG provides interfaces for the added functionality via CORBAservices and CORBAfacilities. CORBAservices provide additional horizontal functionality with a host of services. While it is beyond the scope of this paper to go in-depth about each service provided, the services offered are listed as follows: concurrency control service, event service, externalization service, licensing service, life cycle service, naming service, object trader service, persistent object service, property service, query service, relationship service, security service, and time service[51]. The preceding services offer horizontal functionality needed to create robust and scalable distributed applications. CORBA facilities provide additional horizontal functionality through user interface facilities, information management facilities, systems management facilities, and task management facilities. Vertical facilities intended for unique requirements in certain markets are also available. CORBA has been around for almost a decade has become an industry standard for building enterprise-wide systems. New additions to the language include the ability to pass objects by value. However, due to the open platform nature of CORBA, even that will have its limits since different objects may be implemented in different languages. 3. Java RMI Java RMI is Sun s solution to Java-to-Java distributed computing. RMI is a three-layer architecture consisting of client side stubs and server side skeletons, remote reference layer, and the transport layer. The transport layer facilitates connection set up and management, as well as remote object tracking. The boundaries at each layer are defined by a specific interface and protocol. Each layer can be replaced by an alternate implementation without affecting other layers in the system[10]. RMI has a significant advantage over CORBA with its ability to pass objects by value. This allows full objects to be passed as arguments and return values. Complicated data structures can be sent over the wire[6]. CORBA would require those complex data structures to be first decomposed into simpler data types. By moving class implementations from client to server and vice versa RMI gives the distributed application the ability to pass not only data but behavior as well. This allows remote invocations to be processed locally. Again another shortcoming of CORBA, requiring remote method calls to be processed by the remote object. Building a distributed application in RMI is a four-step process. First interfaces must be defined for remote objects. Implementations must then be created for those objects. Run rmic on the remote implementation classes and make the code network accessible[10].  EMBED Microsoft Word Picture  Sun has added three new interfaces which are built on top of the current Java RMI API. These interfaces provide new techniques to build distributed applications. Leasing, Transactions, and Distributed Events are interfaces built on top of Java RMI to implement next generation distributed applications[11]. Leasing solves the problem maintaining various objects distributed across the enterprise. Java objects negotiate and establish contracts with each other for the use of resources. This additional functionality allows the system to react to network failures, and a host of other problems associated with distributed. Reliability of the system is increases. Transactions support consistency over a set of operations between participating objects. This allows operations to be grouped to guarantee the completion of all operations in a group, or none. Transactions promote consistency over a group of operations. Distributed events allow objects to register to be notified when state changes of other objects occur. This takes the idea of event-based programming in a single environment to a distributed level, enabling new kinds of reliable, event-based services to be introduced into distributed applications. 4. JavaSpaces  A new technology built on top of RMI and introduced by Sun is JavaSpaces. JavaSpaces is a new approach to building distributed applications. JavaSpaces offers a unified mechanism for dynamic communication, coordination, and sharing of objects between Java-based network resources. There is no need to track client, server, or intermediate association of objects by requestor or provider. Full objects can be stored as entries in the space. JavaSpaces can be  integrated with existing software infrastructures. The environment decouples the providers and requestors of network services by providing a single space in the system for sharing, communication, and coordination. The space acts like a dynamic marketplace for distributed objects. JavaSpaces participants communicate by exchanging groups of objects called entries.  Entries are put into a space using a write command. Entries can be examined by using read and take commands. JavaSpaces notifies participants in the system when an entry is added to the space which matches specific criteria. This gets rid of the need for polling. JavaSpaces provides a simplified programming interface, easier development using less code, a unified interface for sharing, communication, and coordination of objects, legacy interoperability, object behavior and data storage, asynchronous communication, multiple implementations, and transparency for users of the system. JavaSpaces addresses two main issues in distributed computing; distributed persistence and distributed algorithms[16]S. Distributed persistence is the ability to store related objects and retrieve them based on value-matching lookup for specific attributes. Distributed algorithms offer a different approach from method-call architectures like CORBA and RMI. Algorithms can be modeled as a flow of objects between participants. Protocols are based on the movement of objects in and out of the JavaSpaces implementation. JavaSpaces offers a unique approach to building distributed applications. It claims to offer robust and scalable distributed applications in an easier environment to develop for. 4. Java and XML With publishing of XML (Extensible Markup Language) 1.0, XML has been foreseen as the next important Internet technology, and the natural and worthy companion to the Java programming language. This aspect has been summed up in the slogan, "XML is portable data, and Java is portable code". 1) What is XML? XML stands for 'Extensible Markup Language' and it is a subset of SGML. With it you can define a document structure using a special grammar called a Document Type Definition (DTD) and add markup to show the structural units in a document[19]. Though sometimes XML is seen as the future of HTML, XML is essentially different from HTML. Actually, HTML is one of SGML DTDs. Any of HTML documents must conform to the constraints defined by this DTD. On the other hand, XML is a metalanguage to let you design your own markup language - DTD. A regular markup language defines a way to describe information in a certain class of documents. XML lets you define your own customized markup languages for different classes of documents. The XML 1.0 standard was approved and published by the World Wide Web Consortium (W3C) on February 10, 1998[20]. An XML document consists of two main logical blocks: prolog and element. Prolog specifies the version of XML being used; the document type declaration within prolog provides a grammar for a class of documents. This grammar is known as a document type definition, or DTD. Each XML document contains one or more elements, which are delimited by star- and end-tags and nest properly within each other. The element, no part of which appears in the content of any other element, is called the root (or document) element. Each element may be associated a group of attributes. Following is part of XML BNF: document ::= prolog element Misc* prolog ::= XMLDecl? Misc* (doctypedecl Misc*)? element ::=EmptyElemTag | Stag content Etag content ::= (element | CharData | Reference | CDSect | PI | Comment)* An XML document is well-formed if it matches the production 'document'. The minimum well-formed XML document contains one element. An XML document is valid if it has an associated document type declaration and if the document complies with the constraints expressed in it. XML is a low-level syntax for representing structured data. You can use this simple syntax to support a wide variety of applications. Generally speaking, itself doesn't support semantic description of data, but XML DTD does. W3C are developing a series of DTDs. HTML is being redeveloped as a suite of XML tag sets so that, although documents will still be marked up using HTML, this will conform to the rules of XML. MathML[21] is intended to facilitate the use and re-use of mathematical and scientific content on the Web, and for other applications such as computer algebra systems, print typesetting, and voice synthesis. To enable simple authoring of TV-like multimedia presentations such as training courses on the Web, W3C has designed the Synchronized Multimedia Integration Language (SMIL)[22]. At mean time, a great deal of proposals and products of XML DTDs are bursting out in a wide range of application. Various groups of companies within a specific industry are working together to define industry-specific markup languages based on XML. 2) Core XML Standards The Document Object Model (DOM)[23] is a platform- and language-neutral application programming interface (API) for HTML and XML documents. It will allow programs and scripts to dynamically access and update the content, structure and style of XML documents. The document can be further processed and the results of that processing can be incorporated back into the presented page. DOM is an object model, which turns a document into a set of objects which are organized logically in a tree-like structure. DOM maintains the property of structural isomorphism, which requires any DOM implementations must create the same structure model while they create a representation of the same document. As an object model, the DOM identifies: The interfaces and objects used to represent and manipulate a document The semantics of these interfaces and objects - including both behavior and attributes The relationships and collaborations among these interfaces and objects The DOM currently consists of two parts, DOM Core and COM HTML. The DOM Core represents the functionality used for XML documents, and also serves as the basis for DOM HTML. The DOM Level 1 specification contains the complete OMG IDL and the complete Java binding for the Level 1 DOM definitions. The Java binding includes 1 Java abstract class and 73 Java interfaces, in which 1 class and 17 interfaces are for DOM Core and 56 are for DOM HTML. Along with the development of XML, the XSL[24] and the Xlink[25] are developed. The XSL, Extensible Stylesheet Language, is a language for expressing stylesheets. It consists of two parts: a language for transforming XML documents, and an XML vocabulary for specifying formatting semantics. Xlink specifies constructs that may be inserted into XML resources to describe links between objects. A link represents explicit relationship between two or more data objects or portions of data objects. Links in Xlink may be very complicated. The following information can be associated with a link and its resources: One or more locators to identify the remote resources participating in the link; a locator is required for each Remote resource Semantics of the link Semantics of the remote resources Semantics of the local resource, if the link is inline Obviously, links in Xlink have two main characteristics: multiple relationship and semantics. 3) Portable Data / Portable Code XML and Java technologies have many complementary features. XML can clearly define data and documents in an open and neutral manner. On the other hand, the Java platform offers a homogeneous computing environment with portable code. Together, XML and Java technologies allow enterprises to apply Write Once Run Anywhere fundamentals to the processing of data and documents. Sun Microsystems' vision for XML and Java technologies is "to provide a platform that embodies portable data and portable maintainable code to produce platform-independent standards-based applications."[26] Sun Microsystems promises to incorporate XML into Java platform standard extension. Java Project X Technology Release 1 delivers basic functionality to read, manipulate, and generate XML text. The XML standard extension will conform to the XML 1.0 specification and will leverage existing efforts around Java platform APIs for XML technology, including the W3C DOM Level 1 Core Recommendation and the SAX 1.0 API. JXML Inc. provides a set of development environment for XML application. Its MDSAX[27] (short for Multi-Document Simple API for XML) is a set of tools for working with Java SAX parsers and parser filters. The SAX (Simple API for XML) is a standard for communications between Java XML parsers and Java. When an XML document is delivered to the the SAX, the SAX may produce 4 types of events: Document events DTD events Error events Entity events In turn, these events are transferred to an XML application. Upon this event-based model, XML applications can read, manipulate, and generate XML text. SAX makes no assumptions about building document trees or performing transformations. SAX is a foundation protocol intended to facilitate low-overhead communications between parsers and applications. MDSAX is a set of tools for organizing, managing, and directing sophisticated SAX processing of XML documents. Using MDSAX, applications can work with multiple document types and can support some of the more sophisticated features of XML processing, like namespaces, Xlink linking, XSL transformations, and architectural forms. In addition to providing i      !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ntegrated developing and running environments for XML, another significant effort on synergy of XML and Java is to express Java Class and Bean metadata as XML documents and convert reversibly Java Object Streams from XML documents while maintaining type safety. The IBM BeanML[28] language can be used to create new beans, access, and configure beans by setting/getting their properties and fields, bind events from some beans to other beans, and call arbitrary methods in beans. Bluestone Software s XwingML comes with a standard DTD that defines the entire Swing/JFC set of classes and properties as well as providing support for all Swing/JFC Listeners. Complete with sample templates for a wide variety of GUI interfaces (menus, frames, and dialogs), users simply author XML documents and XwingML read and dynamically creates the Java GUI. 4) Overall, Java and XML are natural companions, because: XML s markups and character data are encoded in Unicode and Java intrinsically supports the Unicode standard. XML is network version of SGML and Java is network-oriented. XML structures map easily to Java object structures. Both Java and XML are portable across platforms. Many XML components are already available for Java, from parsers to XSL and Xlink engines. Many of the core standards for processing XML are developed with Java in mind, i.e. SAX, DOM, etc. Frameworks for Java XML development like MDSAX are readily available. 5. Java Database Support In a distributed object-oriented system, Java database support should be capable to integrate Java applications with heterogeneous DBMS. Currently developers have a number of choices to program Java databases, including (1) JDBC, (2) SQLJ and (3) ODMG Java Binding. A call-level interface: JDBC JDBC was intended to allow Java developers to quickly start working with the pervasive relational database technology. It was designed also to be a base upon which to build higher-level interfaces and tools. JDBC 2.0 API is the latest update from Sun. It has two main components: the Core API and the Standard Extension. The new features supporting DOC included in the Core API are [36]: SQL3 data type support (SQL types ARRAY, BLOB, CLOB, STRUCT, and REF) Custom mapping of SQL3 user-defined types to Java classes The new features included in the Core API are: Rowsets A rowset is a JavaBeans component; it can be created at design time and used in conjunction with other JavaBeans components in a visual JavaBeans builder tool to construct an application. Establishing Database Connections Using DataSource Objects and the Java Naming and Directory InterfaceTM (JNDI) A DataSource [36] object is a factory for Connection objects. An object that implements the DataSource interface will typically be registered with a JNDI service provider (JNDI). Connection Pooling A connection pool is a cache of open connections that can be used and reused. A PooledConnection [36] object is a connection object that provides hooks for connection pool management. Distributed Transactions Support for distributed transactions allows a JDBC driver to support the standard two-phase commit protocol used by the Java Transaction API (JTA). This feature facilitates using JDBC functionality in Enterprise JavaBeans components [37]. . Current JDBC strategies can be divided into the following three basic approaches: Type 1: client-centric (2-tier) architecture  Figure 1: Two-tier JDBC Type 2: client-server, distributed JDBC architecture  Figure 2: Client-server JDBC server Type 3: a multi-tier distributed object JDBC architecture that uses distributed object framework, such as EJB, CORBA or DCOM   Figure 3: Multi-tier JDBC server Currently there are many commercially available JDBC Driver implementations. DataBroker [38] is the JDBC driver from I-Kinetics, which utilizes CORBA to implement the critical capabilities required by multi-tier enterprise application. By basing a 3-tier JDBC driver on CORBA, the DataBroker can become an assembly of collaborating components rather than a single, large application residing on one server. Using IDL, developers can describe a CORBA-compliant specification to JDBC server objects and then implement them using Java. The server objects can then be made available over the network using IIOP and reused by other applications [39]. This way, I-Kinetics DataBroker implements the JDBC service with additional capabilities such as multi-threaded data streaming and load-balancing. DataBroker provides multi-platform, multi-database and legacy support. An embedded SQL interface: SQLJ Oracle, IBM and Compaq s Tandem Division saw Java's lack of SQL support as a serious challenge for enterprise applications and form a consortium to define the SQL Java standard. In December 1998, this specification called SQLJ was accepted as ANSI standard. SQLJ is a language that embeds static SQL in Java in a way that is compatible with Java's design philosophy. While JDBC requires that the SQL statements be passed as Strings to Java methods, SQLJ preprocessor allows a programmer to instead mix SQL statements directly with Java. The SQLJ preprocessor then translates this Java/SQL mix into Java with JDBC calls. #sql { UPDATE TAB SET COL1=:x WHERE COL2>:y AND COL3<:z }; Code Example 1: A SQLJ Statement SQLJ features include: SQLJ is built above JDBC but does not replace JDBC. A compiled SQLJ application is standard Java bytecode which can run wherever a Java VM, the SQLJ runtime, and a JDBC driver are available. SQLJ translator performs SQL syntax-checking, schema-checking, and type-checking at translation time. At runtime, a SQLJ application communicates with a database through the SQLJ runtime library, which is a thin layer of pure Java code above a JDBC driver. SQLJ provides embedded SQL syntax including transaction management, queries, DDL statements, DML statements, and stored procedure and function calls. SQLJ offers increased portability [40]. SQLJ applications were designed to be vendor-independent: First, the SQLJ syntax is designed to be database-neutral, and the SQLJ translator makes minimal assumptions about the SQL dialect. Second, the consortium members share a common SQLJ translator reference implementation. Third, the SQLJ-generated code and runtime are standard. Oracle has implemented SQLJ directly into Oracle8i and extended standard SQLJ functionality in multiple respects. The extensions include: Support BLOB (binary LOB), CLOB (character LOB), and BFILE (read-only binary files stored outside the database). [41] JPublisher provides Java class mapping corresponding to Oracle8i object types and REFs. [41] The Oracle8i RDBMS is tightly integrated with the Oracle8i EJB server. This enables Enterprise JavaBeans running in the database to use JDBC or SQLJ to access persistent data. [42] Support access to the proprietary language Oracle's PL/SQL. Oracle s Java development tool, JDeveloper, has complete support for authoring and debugging SQLJ programs. In conclusion, Java programmers may access a database using either JDBC or SQLJ. JDBC alone is sufficient but has two weaknesses: The code is lengthy and cumbersome, making complicated queries inconvenient. Errors within SQL statements are not caught until runtime. SQLJ solves both of the issues: SQLJ allows SQL operations with Java host variables to be embedded directly into SQLJ statements, making the code much more concise and convenient. The SQLJ translator checks SQL syntax and semantics and also checks the queries against the database, letting programmers catch SQL errors in development time. However, JDBC and SQLJ should be viewed as complementary technologies because: SQLJ uses JDBC to communicate with databases at translation and runtime. JDBC is required for dynamic SQL, where SQL operations are determined at runtime. SQLJ code and JDBC code can be intermixed within the same program conveniently. Here is the example showing how SQLJ and JDBC can interoperate in one program. import java.sql.*; import sqlj.runtime.ref.DefaultContext; import oracle.sqlj.runtime.Oracle; public class JDBCInterop { // in this example, we use an iterator that is inner class #sql public static iterator Employees ( String ename, double sal ) ; public static void main(String[] args) throws SQLException { if (args.length != 1) { System.out.println("usage: JDBCInterop "); System.exit(1); } /* if you're using a non-Oracle JDBC Driver, add a call here to DriverManager.registerDriver() to register your Driver */ // set the default connection to the URL, user, and password // specified in your connect.properties file Oracle.connect(JDBCInterop.class, "connect.properties"); Connection conn = DefaultContext.getDefaultContext().getConnection(); // create a JDBCStatement object to execute a dynamic query Statement stmt = conn.createStatement(); String query = "SELECT ename, sal FROM emp WHERE "; query += args[0]; // use the result set returned by executing the query to create // a new strongly-typed SQLJ iterator ResultSet rs = stmt.executeQuery(query); Employees emps; #sql emps = { CAST :rs }; while (emps.next()) { System.out.println(emps.ename() + " earns " + emps.sal()); } emps.close(); stmt.close(); } } Code Example 2: Interoperability of JDBC and SQLJ ODMG Java binding Some common ways to implement object persistence under Java include text or binary files, object databases and relational databases. Persistence to flat files is generally not acceptable. Object databases provide direct persistence for Java objects but are not as widely used or supported as relational databases. Currently the ideal solution to implement business object persistence for robust commercial applications is still via relational databases. Java objects are not naturally fit for the two-dimensional tabular structure of relational databases. Java objects cannot be directly saved to or retrieved from relational databases. Java developers working on applications that access relational databases are forced to write massive conversion routines using two different languages, SQL and Java. This is called the  Impedance Mismatch [43] between Java objects and relational databases. ODMG 2.0 Java Binding standard is an efficient way to overcome the  Impedance Mismatch problem. A principle of ODMG Java binding is persistence by reachability [44], that is, objects will become persistent when they are referenced by other persistent objects in the database and will be removed when they are no longer reachable in the manner. The ODMG Java Binding supports database transparency, which means that the application developer s persistent Java class and the database schema are one and the same. At runtime, the ODMG-compliant database software provides a directly mapping between the database and an object cache it manages in the application memory. As the Java application navigatesS among objects, those objects are transparently mapped into the cache. The database tracks the modified objects and write them back to the database at the transaction commit time [45]. It should be clear to see ODMG Java Binding fits perfectly into three-tier or multi-tier architecture [46]. Business logic may be distributed between client and middle tier application server in the manner that best serves the application s goal. The application server provides Java object management and object cache. Data is stored or fetched from a database server sitting at the backend. ODMG Java Binding runs on the application server, where it provides fast, efficient Java object storage.  Figure 4: Java Binding Deployment The ODMG Java Binding standard includes three components [43]. The Java Object Definition Language (ODL) is a database schema definition language used to define the specifications of Java object types that conform to the ODMG Object Model. A simple Java ODL scheme could be like this: /* person.odl */ struct Person { char name[32] (index[], unique[], notnull[]); int age (index); Person *spouse (inverse<Person::spouse>); Person *father; set<Person *> *children (inverse<Person::father>); set<Car *> cars (inverse<Car::owner>); }; struct Car { char mark[32] (index[]); int num (index); Person *owner (inverse<Person::cars>); }; Code Example 3: Java ODL The Java Object Manipulation Language (OML) is a set of classes and other constructs that are added to the Java environment to support the ODMG object model with collections, transactions and databases. The developer can perform transaction and database operation through standardized Java classes for these functions. The binding also supports the standard JDK 1.2 collection classes. Java Object Query Language (OQL) is completely natural to Java programmers, since they get back Java objects, rather than tables. Also, OQL queries can invoke Java methods, and methods can call queries interchangeably in a seamless, flexible working environment. Sun has endorsed the ODMG Java Binding and developed its own ODMG-compliant product, called Java Blend [47], which implements the Java Binding on relational databases. Java Blend makes it easy for developers to build business application s that integrate Java objects with enterprise data. Another two commercial products implementing ODMG Java Binding are: (1)Visual BSF "! (VBSF) [48] is an all Java object-relational framework that enables Java objects to be persistent to relational databases. The distributed version is a middleware product that allows developers to deploy persistent objects in a distributed (3-tier) configuration. The current distributed version is based on RMI. No need to pre-processing code, post-processing byte code, forcing the use of a base class, or extending persistent classes. VBSF is designed to easily integrate with most existing legacy databases. VBSF also provides specific support for many major database products. In-memory queries are queries that are processed directly from a cache without accessing the database. Currently, in-memory queries are only utilized in client caches. (2)POET s Object Server 5.0 [49] is an object database management system for complex data application. POET's Java SDK and SQL Object Factory adds distributed and enterprise critical feature: A POET database is actually two databases, the database and the dictionary. The dictionary and database are automatically created when the programmers call the POET Java pre-processor. SQL Object Factory is able to transparently and automatically map object classes into relational database tables. POET's Java SDK and SQL Object Factory support advanced features of ORB support, nested transactions, object level locking, and flexible concurrency control. A deployment may be a 'Ultra-Thin' client combined with an OMG-compliant CORBA middleware service to enable true distributed computing, with application servers and distributed business objects. 6. Enterprise JavaBeans More and more developers want to write distributed transactional applications for enterprise and leverage the speed, security and reliability of server-side technology. Enterprise JavaBeans provides a standard server-side component model [31] for multi-tier applications. Enterprise JavaBeans defines distinct roles in dealing with enterprise application lifecycle. Enterprise JavaBeans allows for fast focus-on-business development of enterprise applications, customizable deployment and administration. Enterprise JavaBeans saves time and effort of application developers by separating component level APIs from the concerns of lower level system programming. Enterprise JavaBeans container and server providers are responsible for providing transaction, security and persistency supports as well as multithreading, resource pooling and other low-level facilities. Enterprise JavaBeans as standard server side component model [31] Enterprise Beans are components of distributed transaction-oriented enterprise applications. Enterprise Beans are created and managed at runtime by a container. Enterprise Beans can be customized at design and deployment time using the container s tools. The container implements facilities to mediate client access to the enterprise Beans. The EJB platform consists of several standard APIs that provide access to a core set of enterprise-class infrastructure services. The set of services are implemented on different platforms using different products and technologies. The EJB APIs provide a common interface to the underlying infrastructure services to enable portability, platform-neutral and vendor-neutral environment, allow integration of existing services, and promote industry acceptance. Enterprise JavaBeans supports  Write Once, Run Anywhere (WORA) portability. 100% pure Java clients can always invoke Enterprise JavaBeans methods no matter where the Beans are located and how they are implemented. Enterprise Beans can run on any EJB compliant application server. Enterprise JavaBeans can be deployed over a cluster of EJB servers to take advantage of the computing power and services provided by each server. Enterprise JavaBeans act like clients when requesting services from other enterprise JavaBeans and applications. Enterprise JavaBeans technology makes it possible to develop portable multi-tier applications with heavy-duty servers and thin-clients. The applications may have Beans wrapping various databases, providing interface to legacy applications, and implementing additional business functions. The clients are very thin GUI software for interacting with users, requesting services from servers and presenting results. Enterprise JavaBeans multi-tier application model s support for interoperability is ideal for serving critical demands of enterprise computing. By moving business execution to servers, the EJB multi-tier applications can be centrally managed and monitored. The organization-wide network provides improved performance over the traditional fat-client client/server model. The maintenance and upgrading of the applications can be carried out well in-control. New versions of clients can be easily deployed. Automatic upgrading feature can be built into the clients to enable pushing new versions in a timely manner. The applications sustain server changes, network topology changes and deployment policy changes as long as the infrastructure supports Enterprise JavaBeans. The applications can also be customized to fit changing needs of the organizations or to be adopted by other organizations. Enterprise JavaBeans Roles Enterprise JavaBeans 1.0 specification defines six distinct roles in the application development and deployment workflow. Each role may be performed by a different party. In some cases, a single party may perform several roles. For example, most container providers are also EJB server providers. [34] 1) Enterprise Bean Provider  An enterprise Bean provider is an application domain expert. The product of an enterprise Bean provider is reusable enterprise Beans components, which are packaged in an ejb-jar file. 2) Application assembler  An application assembler is an application domain expert. The application assembler creates applications or new enterprise Beans by using enterprise Beans remote interface and home interface. 3) Deployer  A deployer is an expert at a specific operational environment. A deployer is responsible for deployment of enterprise JavaBeans. A deployer uses tools provided with the EJB servers to customize the business logic of the enterprise JavaBeans, map security roles assumed by the enterprise Beans and modify the attribute settings of the enterprise JavaBeans. 4) EJB server provider  An EJB server provider is a specialist in the area of distributed transaction management, distributed objects, and other lower-level system services. Typically, an EJB server provider is an OS vendor, middleware vendor or database vendor. 5) EJB container provider  An EJB container provider is a specialist in system-level programming. The container provider insulates the enterprise Bean from the underlying EJB server by providing a simple and standard API between the enterprise Bean and the container. 6) System Administrator  A system administrator uses tools coming with the EJB server to monitor and manage the enterprise Beans. EJB contracts EJB specifies contracts to ensure that the product of each role is compatible with the product of the other roles. EJB specifies standard APIs for client s view contract, component contract and ejb-jar contract. 1) Client s view contract is between a client and a container. It includes the obligations, such as object identity, object creation, object locating and business method invocation, that are to be fulfilled by the enterprise Bean provider and the container provider collaboratively. 2) Component contract is between an enterprise Bean and its container. It includes enterprise Bean instance s view of its life cycle, runtime environment and services provided by the container for the enterprise Beans. 3) ejb-jar is a standard format used by EJB tools for packaging enterprise Beans with their declarative deployment information. It includes a manifest file, Java classes for the enterprise Beans, deployment descriptors and runtime environment requirement properties. The following is an example showing a Trader Bean public interface TraderHome extends EJBHome { Trader create() & } public interface Trader extends EJBObject { public TradeResult buy ( ... ) ... public TradeResult sell ( ... ) ... public double getStockPrice(String stockSymbol) ... } public class TraderBean implements SessionBean { public void ejbRemove() throws ... { ... } public void ejbActivate() & { & } public void ejbPassivate() ... public void setSessionContext(SessionContext ctx) ... public void ejbCreate () ... public TradeResult buy( ... ) ... public TradeResult sell( ... ) ... public double getStockPrice(String stockSymbol) ... } where TraderBean is the enterprise Bean, Trader is the remote interface, and TraderHome is the home interface. Each create method in TraderHome has a corresponding ejbCreate method in TraderBean. They are invoked by clients to get a reference to an enterprise Bean instance before the business method can be called. Each business method in Trader has a corresponding method in TraderBean. Besides these methods that build the enterprise Bean s client s view contract, other methods in TraderBean forms the enterprise Bean s component contract for persistence and state management. The container implements the interfaces TraderHome and Trader, and delegates all method invocations to TraderBean instances. The implementations are basically container-side skeletons compliant with Java RMI specification. EJB types and Beans lifecycle There are two types of enterprise Beans: [Pawlan 1999;Matena et al. 1998;Thomas 1998] 1) Session Beans are objects executing on behalf of a single client. Session Beans are short-lived and do not survive EJB server crashes. Session Beans can be transactional. Session Beans can access shared persistent data sources but do not represent the data sources. A typical EJB server and container provide a scalable runtime environment to execute a large number of session Beans concurrently. Session Beans can be stateful or stateless. A stateful Session Bean instance is created on demand when a client invokes a create method of the Bean s home interface.  EMBED Microsoft Word Picture The client obtains a reference to the remote interface of the instance. The instance is removed when the client invokes remove method of the Bean s remote interface. A stateless Session Bean does not contain state variables, therefore the container may create a pool of instances and choose any of them per each business method invocation. Stateless Session Bean must have a single create method with no arguments. Stateless Session Beans are more scalable and allow the container to manage resource more efficiently. However, the clients may have to implement mechanism to manage the sessions. 2) Entity Beans are persistent objects representing data in the database. Entity Beans are shared by multiple users. Entity Beans are transactional. Entity Beans can be long-lived and survive EJB server crashes. A crash is transparent to the client. A typical EJB server and container provide a scalable runtime environment for a large number of concurrently active entity Beans. Entity Beans are stateless and can be pooled by the container. The container may choose whichever instance to serve the business method invocation from clients. Enterprise Beans provider may either implement Bean-managed persistence or let the container to synchronize the Bean and the underlying database. Services provided by EJB containers Support for Transaction EJB supports flat transactions modeled after OMG OTS [32]. EJB transaction support is through JTS API  Java s mapping of OTS. EJB servers support declarative transactions and implement demarcation mechanisms for the defined types of declarative transactions. EJB servers also support limited Bean-managed transactions. A transaction may be started by a client or the Bean itself. The container may also start a transaction automatically for an enterprise Bean. The declarative transaction management is controlled by a transaction attribute associated with each enterprise Bean. 2) Support for Distribution EJB support for distribution is through Java RMI API. Java RMI API allows a client to invoke an enterprise Bean object using any distributed object protocol, such as Java native JRMP and the industrial standard IIOP protocol. Java RMI API makes access to an enterprise Bean object location transparent to a client programmer. The companion EJB-CORBA mapping specification [29] defines the standard mapping of Enterprise JavaBeans to CORBA to enabled enhanced network interoperability. 3) Support for Security EJB adds additional support to the existing Java programming language security API [30]. The container provides the enterprise Beans with the identity of the caller. The enterprise Beans provider may decide to implement security mechanism in the Bean. EJB security attributes may be declarative, in which cases EJB servers are responsible for enforcing the declared and customized security. EJB supports both user-based and user-role-based access control. 8. Conclusions and Future Research CORBA, RMI, and JavaSpaces offer distributed solutions through different approaches. Not one technology is the best solution for all distributed computing solutions. Different requirements will require different approaches. Each technology suits different needs, and the underlying functionality of the system will dictate which approach to use. Enterprise JavaBeans components are truly portable across EJB-compliant application servers. EJB applications are highly independent of the platforms, protocols and middleware infrastructures. EJB applications are highly customizable and scalable. EJB technology built-in transaction, persistence and security features are critical to enterprise computing. Enterprise JavaBeans technology is backed by major application server vendors such as IBM, BEA, Sun, Oracle, etc. EJB is also supported by major development tool vendors such as Borland and Symantec. EJB technology opens a new arena for enterprise application development. Future research of Java support in supporting of distributed object computing: 1. Continued investigation into other distributed architectures such as Jini, and extensions made to the Java language should be further explored. Evaluation of real-world solutions, and further developments in each of the technologies discussed should be monitored as well. 2. Enterprise Java platforms Modern database servers have been evolving to adapt to more complicated data application. Oracle8i is a typical example of these new platforms, which not only provide database service, but also integrate support for Enterprise JavaBeans, CORBA services and Java development tools. They will play an important role in Java database support for distributed enterprise computing. 3. Object database systems The most powerful and natural option is a truly object oriented database management system (ODBMS) that allows easy storage of Java objects. ODBMS need to be flexible, scaleable, and reliable. And it needs to provide features such as multi-user/concurrent access, queries, user authorization, and so on. 4. Enterprise JavaBeans This research is based on Enterprise JavaBeans specification 1.0. The current specification version defines the standard APIs between EJB providers and EJB containers. It also includes limited Bean-managed features. In the future release, the interface between EJB containers and EJB servers may be specified. Advanced programmers may have more choices to leverage the power of the facilities provided by the servers. References Sutherland, Doug.  RMI and Java Distributed Computing . 1998,  HYPERLINK "http://www.javasoft.com/features/1997/nov/rmi.html"www.javasoft.com/features/1997/nov/rmi.html  Using CORBA and Java IDL 1997,  HYPERLINK "http://www.javasoft.com/products/jdk/1.2/docs/guide/idl/jidlUsingCORBA.html"www.javasoft.com/products/jdk/1.2/docs/guide/idl/jidlUsingCORBA.html  Java Distributed Object Model , 1997,  HYPERLINK "http://www.javasoft.com/products/jdk/1.1/docs/guide/rmi/spec/rmi-objmodel.doc.html"www.javasoft.com/products/jdk/1.1/docs/guide/rmi/spec/rmi-objmodel.doc.html Wettach, Heidi  Comparison of IIOP, RMI, HTTP 1997,  HYPERLINK "http://Adala.smith.cis.syr.edu/~hlwettac/cis700/Compare.html"http://Adala.smith.cis.syr.edu/~hlwettac/cis700/Compare.html Minton, G.  Report on: IIOP Specification: A closer Look 1997,  HYPERLINK "http://olympus.cs.ucdavis.edu/dos/iip.html"http://olympus.cs.ucdavis.edu/dos/iip.html  Java Remote method Invocation 1998,  HYPERLINK "http://www.javasoft.com/marketing/colateral/rmi_ds.htm"http://www.javasoft.com/marketing/colateral/rmi_ds.htm Caribou Lake Software  RMI versus CORBA 1997,  HYPERLINK "http://www.cariboulake.com/techinfo/rmi_corba.htm"www.cariboulake.com/techinfo/rmi_corba.htm  IIOP (Internet Inter-Orb Protocol) 1998,  HYPERLINK "http://www.whatis.com/iiop.htm"www.whatis.com/iiop.htm  White Paper: JavaSpaces 1998,  HYPERLINK "http://java.sun.com/products/javaspaces/whitepapers/jspaper.pdf"http://java.sun.com/products/javaspaces/whitepapers/jspaper.pdf  White Paper: Java RMI 1998,  HYPERLINK "http://java.sun.com/products/javaspaces/whitepapers/rmipaper.pdf"http://java.sun.com/products/javaspaces/whitepapers/rmipaper.pdf  White Paper: Java RMI: A New Approach to Distributed Computing 1998,  HYPERLINK "http://java.sun.com/products/javaspaces/whitepapers/dcpaper.pdf"http://java.sun.com/products/javaspaces/whitepapers/dcpaper.pdf  JavaSpaces FAQ 1998,  HYPERLINK "http://java.sun.com/products/javaspaces/faqs/jsfaq.html"http://java.sun.com/products/javaspaces/faqs/jsfaq.html  Java RMI FAQ 1998,  HYPERLINK "http://java.sun.com/products/javaspaces/faqs/rmifaq.html"http://java.sun.com/products/javaspaces/faqs/rmifaq.html  JavaSpaces Specification 1998,  HYPERLINK "http://java.sun.com/products/javaspaces/specs/js.pdf"http://java.sun.com/products/javaspaces/specs/js.pdf  Java RMI: Case Study: Allmerica Financial 1998,  HYPERLINK "http://java.sun.com/products/javaspaces/casestudies/allamerica.pdf"http://java.sun.com/products/javaspaces/casestudies/allamerica.pdf  JavaSpaces Datasheet 1998,  HYPERLINK "http://java.sun.com/products/javaspaces/datasheets/jssheet.pdf"http://java.sun.com/products/javaspaces/datasheets/jssheet.pdf  Java RMI Datasheet 1998,  HYPERLINK "http://java.sun.com/products/javaspaces/datasheets/rmisheet.pdf"http://java.sun.com/products/javaspaces/datasheets/rmisheet.pdf  Java Distributed Computing Overview 1998,  HYPERLINK "http://java.sun.com/products/javaspaces/datasheets/dcsheet.pdf"http://java.sun.com/products/javaspaces/datasheets/dcsheet.pdf [19] Frequently Asked Questions about the Extensible Markup Language,  HYPERLINK "http://www.ucc.ie/xml/"http://www.ucc.ie/xml/ [20] Extensible Markup Language (XML) 1.0, W3C Recommendation 10-February-1998,  HYPERLINK "http://www.w3.org/TR/1998/REC-xml-19980210"http://www.w3.org/TR/1998/REC-xml-19980210 [21] Mathematical Markup Language (MathML) 1.0 Specification, W3C Recommendation 07-April-1998,  HYPERLINK "http://www.w3.org/TR/REC-MathML/"http://www.w3.org/TR/REC-MathML/ [22] Synchronized Multimedia Integration Language (SMIL) 1.0 Specification, W3C Recommendation 15-June-1998,  HYPERLINK "http://www.w3.org/TR/REC-smil/"http://www.w3.org/TR/REC-smil/ [23] Document Object Model (DOM) Level 1 Specification Version 1.0,W3C Recommendation 1 October, 1998,  HYPERLINK "http://www.w3.org/TR/REC-DOM-Level-1/"http://www.w3.org/TR/REC-DOM-Level-1/ [24] Extensible Stylesheet Language (XSL) Specification, W3C Working Draft 21 Apr 1999,  HYPERLINK "http://www.w3.org/TR/WD-xsl/"http://www.w3.org/TR/WD-xsl/ [25] XML Linking Language (XLink), World Wide Web Consortium Working Draft 3-March-1998,  HYPERLINK "http://www.w3.org/TR/1998/WD-xlink-19980303"http://www.w3.org/TR/1998/WD-xlink-19980303 [26] JP Morgenthal, Portable Data / Portable Code: XML & JavaTM Technologies,  HYPERLINK "http://java.sun.com/xml/ncfocus.html"http://java.sun.com/xml/ncfocus.html [27] MDSAX 1.0 (Production Release),  HYPERLINK "http://www.jxml.com/mdsax/index.html"http://www.jxml.com/mdsax/index.html [28] Bean Markup Language,  HYPERLINK "http://www.alphaworks.ibm.com/tech/bml"http://www.alphaworks.ibm.com/tech/bml [29] Rohit Garg, Enterprise JavaBeans to CORBA Mapping 1.0, Sun Microsystems, 1998 [30] Li Gong, Marianne Mueller, Hemma Prafullchandra and Roland Schemers, Going Beyond the Sandbox: An Overview of the New Security Architecture in the Java Development Kit 1.2, in Proceedings of the USENIX Symposium on Internet Technologies and Systems, Monterey, California, 1997 [31] Vlada Matena and Mark Hapner, Enterprise JavaBeans Specification 1.0, Sun Microsystems, 1998 [32] OMG Object Transaction Service (http://www.omg.org/corba/sectrans.htm#trans) [33] Monica Pawlan, Enterprise JavaBeans: Working with Entity and Session Beans, Java Developer Connection, JavaSoft [34] Michael Shoffner, Writing a session EJB, JavaWorld, July 1998 [35] Anne Thomas, Enterprise JavaBeans Technology, Patricia Seybold Group, 1998 [36] JDBC 2.0 Core API and Standard Extensions API javadoc  HYPERLINK "http://www.javasoft.com/"http://www.javasoft.com [37] Laura Wang,  Business-Critical Connections, the JDBC API , JavaSoft Features, Apr. 1999  HYPERLINK "http://www.javasoft.com/features/1999/04/jdbc.html"http://www.javasoft.com/features/1999/04/jdbc.html [38]  OPENjdbc: The Future of Enterprise Database Access with JDBC , I-Kinetics White Paper, [39] Mike Higgs,  Universal Data Access Using Multi-tier Architecture: Foundation for the Enterprise , Oct. 1998  HYPERLINK "http://shrike.depaul.edu/~iilyas/ds520/enterpise_data_acess.htm"http://shrike.depaul.edu/~iilyas/ds520/enterpise_data_acess.htm [40]  Oracle Extends Support for Standards Based SQLJ , Java Developer s Journal, Vol. 4, Issue 2, Feb. 1999. [41] Thomas Kurian and Dave Rosenberg,  Oracle8i&Java, An Enterprise Java Platform , Java Developer s Journal, Vol. 3, Issue 11, Nov. 1998. [42]  Oracle8i Features for Java , Oracle White Paper, Feb. 1999  HYPERLINK "http://www.oracle.com/"http://www.oracle.com [43] Douglas Barry and Torsten Stanienda,  Solving the Java Object Storage Problem , IEEE Computer, Vol. 31, No. 11, Nov. 1998. [44] Douglas Barry and David Jordan,  ODMG: The Industry Standard for Java Object Storage ,  HYPERLINK "http://www.odmg.org/"http://www.odmg.org, Sep. 1998. [45] Andrew Wade,  How to Store and Share Your Java Objects , Java Developer s Journal, Vol. 3, Issue 4, Apr. 1998 [46]  Why Use an ODBMS? A Comparison Between Relational and Object Oriented Databases for Object Oriented Application Development , POET Technical Reference  White Paper, [47]  Java Blend: Integrating Java Objects With Enterprise Data , JavaSoft White Paper, Sep. 1998 [48] POET Object Server Suit,  HYPERLINK "http://www.poet.com/"http://www.poet.com [49] Visual BSF,  HYPERLINK "http://www.objectmatter.com/"http://www.objectmatter.com [50] Burghart, Ted.  Distributed Computing Overview , 1998  HYPERLINK "http://www.quoininc.com/quoininc/dist_com.html"http://www.quoininc.com/quoininc/dist_com.html [51] Rosenberger, Jeremy CORBA in 14 DAYS Indianapolis: Sams Publishing 1998 [52] Schmidt, Douglas C.  Developing Distributed Object Computing Applications with CORBA  HYPERLINK "http://www.acl.lanl.gov/CORBA"http://www.acl.lanl.gov/CORBA [53] Schmidt, Douglas and Vinoski, Steve  Introduction to Distributed Object Computing (Column 1) C++ Report Jan 1995 [54] Vinoski, Steve  CORBA: Integrating Diverse Applications Within Distributed Heterogeneous Environments  HYPERLINK "http://www.acl.lanl.gov/CORBA"http://www.acl.lanl.gov/CORBA Appendix A. Group members Team members and topics are: Walter McClure: CORBA and RMI Chenzhong Wang: EJB Xu Ma: Java and database support Wei Lin: XML and Java B. Component breakdown (1) Middleware and Distributed Architectures 1. Overview  Introduce RMI, JavaSpaces, CORBA 2. CORBA  Examine the infrastructure of technology and how it fits into Java and DOC 3. Java RMI  Innerworkings of API as well as extensions to the technology 4. JavaSpaces  Sun s new distributed environment provides new approach to build distributed systems (2) XML and Java XML is the technology of choice for exchanging structured information over the Internet, Intranets and Extranets. Web-based commerce, enterprise application integration and software system design are now set to take advantage of the many benefits of XML. DOM, a standard API for XML Portable data / portable code (3) Java database support 1) JDBC provides database access via Java that's independent of both the platform and the database host system the application runs on. 2) SQLJ is a language that embeds static SQL in Java in a way that is compatible with Java's design philosophy. 3) ODMG Binding for Java is a technology available today for Java object storage. (4) Enterprise JavaBeans Enterprise JavaBeans as standard server component mode Roles in Enterprise JavaBeans development and deployment workflow Enterprise JavaBeans contracts Enterprise JavaBeans types and lifecycle Persistence, distribution, transaction and security IIOP N. P. N. P. Network Protocol Client JDBC Driver DBMS JDBC Client DBMS JDBC Server N. P. CORBA. P. JDBC Client DBMS CORBA JDBC Server Client Database Server . . . GUI Application Logic Application Logic Object Management Application Logic Object Management Application Servers   JavaSpaces Application JavaSpaces Application Figure: Client invoking method on remote object. While the method is invoked from the client, it is up to the remote object to process the request and return any return values from the operation JavaSpaces Application[14]  TXZn   p @#X#&N''.j2 55 5H9Z9=L@CCC C"CPKTKXKQX@Z\\`eZgdghhhDhFhʾUj VU jUCJ65aJOJQJCJ6aJOJQJCJ5aJOJQJCJnHtH^JaJOJQJCJ5aJOJQJCJaJOJQJCFhHhJhjmoqqrrrruuuuwxxxxxxBDFHJLNPRTVXZNDHxh~j$6^<rCJmHsHaJOJQJ jUCJaJOJQJH*CJnH tH aJOJQJCJnH tH aJOJQJOPd >Bbf bhBHLdj  J N#^%*(**+,,.p../1@34CJnH tH aJOJQJCJ5nHtH^JaJOJQJCJPJaJOJQJCJnHtH^JaJOJQJCJmHsHaJOJQJ jU0J<CJaJOJQJCJaJOJQJ=444;J<>BF.KNQJQSSSSSS\UdUUW W0WZZ.Z\\D\0^8^`^6_R_`a2a2c:c^cdddfbggggggDhJhhhhhFiJiNiiiƷB*phCJ9aJOJQJB*phCJ9aJOJQJB*phCJ9aJOJQJCJ6aJOJQJUj,CJaJOJQJCJaJOJQJCJ5aJOJQJ=ijjPjVjjjkk kBkFkJkkkkkBlFlTlhlllll2m>mTmhmmmmmno>oRop,pp*q>qHqTqqqrrsssvwwww0x2x4x6x(y6yyz⻱ UjUUj VUCJ6aJOJQJCJaJOJQJB*phCJ9aJOJQJB*phCJ9aJOJQJB*phCJ9aJOJQJB*phCJ9aJOJQJ?zz8{D{||}X~Z~LĂXd0v2.̗0"Z:>RУңPRT.04@BDڧܧHJܨިXZƳƳƳƳjUjUjU0J;CJaJOJQJjUUCJ5aJOJQJUjCJaJOJQJCJ6aJOJQJCJaJOJQJUjDCJaJOJQJ=ZܩީLNP|~NP̬άЬ$&*حڭܭ  NPjlpFHJʰ̰а\^xz~68:ڳܳfj UjUjUj Uj]UjUjU0J;CJaJOJQJjUUCJaJOJQJBfhjڴܴ"$~ "~<>ֹعڹXZ^PRTлһ`bؼڼ|~DF dfhjUjUjFUjWUjfUjw Uj Uj UCJaJOJQJ0J;CJaJOJQJUj U?h VXZXZjl  npr lnpZ\^RJ^tvxjtUjUjUj?UjvUjUjUj_UCJaJOJQJU0J;CJaJOJQJC246X:<>XZ6P JLLJLNtvv@BfhprHJCJ>*aJOJQJj_UjUjUj~UjUjUCJaJOJQJ0J;CJaJOJQJjUU@:<, ^`bX("HRVxpẺŰ#B*OJQJCJmH sH PJ^JaJCJ6aJOJQJCJ^JaJOJQJCJ5aJOJQJCJ5aJOJQJjUCJaJOJQJ0J;CJaJOJQJUj.U7&(@LNrt&RVdh5656 Uj$ Uj#B*OJQJmH sH PJ^JaJCJ#B*OJQJCJmH sH PJ^JaJ#B*OJQJCJmH sH PJ^JaJ# VXZpdh$a$dh$a$dh$a$dh$a$dh$a$Idh  ~= z9!v% & Fdhdh$a$dh$a$dhdhdh  & Fdh$a$   >dh$a$^]` >dh$a$^]`Ddh dh$a$^]`dh$dh & Fdhdh$a$dh$a$dh$a$dh$a$dh$a$dh$a$dh$a$r B#Z#&P''.l2J9\9=N@u Edh$a$^]` Edh$a$^]` dh$a$^]` dh$a$^]`Cdh$a$Cdh$a$Cdh$a$>dh$a$ >dh$a$^]`>dh$a$ >dh$a$^]` >dh$a$^]` N@CRKVKXKQXBZ\]`ehLh{s?dh$a$ ?dh$a$^]`?dh$a$ ?dh$a$^]` ?dh$a$^]` ?dh$a$^]`?dh$a$?dh$a$?dh$a$?dh$a$?dh$a$ Edh$a$^]` Edh$a$^]` Lhjmoqruuwxxz8}R?dh$a$?dh$a$?dh$a$?dh$a$ ?dh$a$^]` ?dh$a$^]`?dh$a$?dh$a$?dh$a$?dh$a$?dh$a$?dh$a$?dh$a$?dh$a$&Fʐ(2l{ dh^]` dh$a$^]` dh$a$^]` dh^]` dh^]` dh^]` dh^]` dh$a$^]` dh$a$^]`CdhCdh$a$>dh$a$ T ^>^έ<:& dh$a$^]` dh$a$^]` dh^]`dh & Fdh 8F^]` dh$a$^]`dh$a$ & Fdh ^]` dh$a$^]`0F`|̿ b.6h|Cdh$a$>dh$a$E & Fdh ^]` dh^]`Cdh$a$dh$a$ & Fdh dh$a$^]`|L 0yk Edh$a$^]`h & F dh 8^8]` dh$a$^]`h & Fdh$a$^8]` Edh$a$^]`h & Fdh^8]` dh$a$^]` & F dh$a$^8]`Cdh$a$ & F dh 8^8]` @DXZ~ dh^]` dh^]` & Fdh$a$^8]`dh dh^]` & Fdhdh dh^]` & Fdh^8]`dh$a$ dh$a$^]`h & Fdh^8]`PF|C & Fdh$a$ 8^8]`C & Fdh$a$^8]` dh^]` dh^]`  & Fdh$a$IdhIdhCdh$a$Cdh$a$ & F dh 8^8]`Cdh$a$ & Fdh Jzjl& ~p & Fdh^8]` & Fdh$a$^8]` dh$a$^]` & Fdh$a$ 8^8]` & Fdh 8^8]` & Fdh$a$^8]` & Fdh$a$^8]`?dh$a$ & Fdh$a$^8]` 8`>tRf u dh$a$^]` & F dh 8^8]` & Fdh^]`dh dh$a$^]` & F dh$a$^8]` & F dh^8]` dh$a$^]` & Fdh$a$^8]` dh^]` f @ dh$a$^]`dh & Fdh dh^]` dh^]` dh^]` dh^]` dh^]` dh^]` dh^]` Gdh$a$^]`Cdh$a$ @Bdf dDJLf  L P#Idh$a$  ~= z9!v%^]`Idh$a$  ~= z9!v%Idh v%Idh  ~= z9!v%P#`%,(*+,../ 1B3t_ & Fdh$a$^8]`dd & F dh$a$^8]` dh$a$^]` & Fdh$a$ 8^8]` & Fdh$a$ 8^8]` & Fdh$a$^8]` dh$a$^]` ?dh$a$^]`Idh$a$  ~= z9!v% B344;L<>BF0KNQLQSv dh$a$^]` dh$a$^]` dh$a$^]` dh$a$^]`dh$a$ dh$a$^]` dh$a$^]` & Fdh$a$dh$a$dh & Fdh$a$^8]`dd SS^UWZ\2^8_T_`4cdvh dh$a$^]` dh$a$^]` dh$a$^]` & Fdh$a$ dh$a$^]` dh$a$^]` dh$a$^]` dh$a$^]` dh$a$^]` dh$a$^]` dh$a$^]` dgdgggggFhhhHiLiNiu dh^]` dh^]` dh^]` dh^]` dh^]` dh^]` dh^]` dh^]` dh^]` dh^]` dh$a$^]` dh$a$^]` Nii jRjjkkDkFkkkDlHlp{sdh$a$ dh^]` dh^]` dh^]` dh^]` dh^]` dh^]` dh^]` dh^]` dh^]` dh^]` dh^]` dh^]` prrsvy|NƂZw dh$a$^]`dh$a$ & Fdh$a$ dh$a$^]` dh$a$^]` dh$a$^]` dh$a$^]` dh$a$^]` dh$a$^]` & Fdh$a$dh$a$ f2x40Η2$\{sdh$a$ dh^]` dh^]` dh^]` dh^]`?dh$a$ dh^]` dh$a$^]`?dh$a$dh dh$a$^]` dh$a$^]` dh$a$^]` <>T2ާ\(nΰ|޴\Իܼdh$a$ & Fdhdh dh$a$^]` dh$a$^]`ܼH"nTyk dh$a$^h]`dh$a$ dh$a$^h]` dh$a$^h]` dh$a$^h]` dh$a$^h]` dh$a$^h]` dh$a$^h]` dh$a$^h]` dh$a$^h]` dh$a$^h]` L`vZ<\8RNdhdhdhdhdhdhdhdhdhdh dh$a$^h]` dh$a$^h]` dh$a$^h]` dh$a$^h]` dh$a$^h]`NNxDL>. >dh$a$^]`>dh$a$dhdhdhdhdhdhdhdhdhdhdhdhdhdhdhZ*$ dh^]` ?dh^]` ?dh^]` ?dh^]` ?dh^]` ?dh^]` & Fdhdhdhdhdh dh^]`>dh$a$>dh$a$JTz r|~F & Fdh$a$ 8^8]` ?dh^]` ?dh^]`dhCdhdh  & Fdh? & Fdh "$<>@L$a$$a$$a$$a$$a$$a$$a$$a$$a$LNbdf~A$$a$$a$$a$$a$$a$$a$F&(LNrt$&TV  & F<A$ & Fdh$a$ 8^8]`0/ =!"#$2P1h0p3P(20 [$@$NormalmH <A@<Default Paragraph Font  l,b$jL I?+&2 @n(  6   AB S  ?t@(@GTimes New Roman5Symbol3& Arial"h"5F"5F!0Chenzhong WangChenzhong WangY bjbjWW >==] UUU_aaaaaa$PDbU3"UUU_M___U _U_____ @__  jUmHN N!"#g$h%n2jL I?+&PNG  IHDRcgAMA pHYs{0 IDATxh?zwm+VN;Un=YA[lM`XC)!4X)c L.9/=n.{LFLcΪGT"?4KZWiwzWkU;cvvvf}y}L0Rj(((((((l+`5ڼWNI{OYIbJ/S DisEE+\t5}*:=2%\mx#|ϳ*58H2A$FXyr,.)g}""8w":OL=w>zxV[u0C[~_%9E=)8r4f_RXS|RӠg_)R5f־HoKFnj(i. Ե叮#ȯ^dۯ~n?;?cCVsͳ׽ڐRU[OE([G@mb؟wP,:DFK:i?y)M.mu53~)#~ږe"]F!p6Vj\M=;rnT=Y}`UMq7/W>{o:4޽Ys{`wkSl-/źOUϲ2C>BB_7YIl'i!K8|0t]` ;z!7n~r1%FfSZ7K[7@C|"2oa9-bq˒8![]?ۤjt3mGgJc[e,&L}5Ȅ8 ;0j|C׎5?=;6 (/* gaT(>-2" mn;zb:F;cPQ CykjaDShE˲",JErwocH}E!}Qq.u@E(Fрx{'Z K|p5o]5i}e6ތQ1F-0u}&4mG8v -s쿷1ozGF=D~L׶/7SV¨ѴK -=0!RVp^nm;Hrh3:[v})?L,F4W\}{u SF5vDalM/,og8[Xu̬6r°i)OV9.ؔ9ZU%WeߑooKݜǾ|Ϛ'YUo TZ>Ԍ9w xE7_ӆ'bSUOX!^z^V&_9,Ri*e`:_rnqYׅ쫔 V)9D.LfN[7+ܰU(r4ߓ4ntk-$ل[Mvªy+{btjNK3BЭc{=$}.g.cP%MϾ*?=tVyW87'knF:)o7iRJ)#e髲uxQzA/lOM˅9HyM릀Yxv#1i/1虨Ѻȗ/>p*s68dY2LL- Z3f6ȯ3/RAu"08FN2ǯv)ܾȘ ֮V keɫ~= mq`Di8o"-֋я[:3qmg uɔu߹4DHRL^cNPI*aEluC7F`[]\j6?^hNɅa)[+^<{rrnR?''3$(+8KF/e*;bTJubu/3!3$DqCBhe/1.גb{ h`W\z#usKDo&w[vhU"frw$V+Rю$fxg[Í)$0=*>eFtd#dulѪcL}=["'s3;.ƛѶ/ǟn 2tGljiw4ݩ +>;kj=c`߿ 4*|=A BA*YmD3QɎHͤjy) qYءtڡg3[Lf:ooHlk\o5*9JP8'cXQ kiyw]ӭEIxe(.4NjO펎?o>g,cg(Ǵg-Da4~[9MrEr*sq" ~]5z?b3V1iӞZfKc4Fz誚Y|j՘͎Ӟ>vO3nȣ_ݗxp02!ǿ,8ӿkf}L?cG ֯w>ۿ:|뇿y/2W{k_M.oÿ\L*?}U_hj:yO'^0~DG[.YL;A$=i KtĀIpQbH^iteo3g7E2+m)<?Sx*@y(lǨ`?O/ީ[/W Sp"0xd6LQD#u&iھWZQz EgcU6hEnp7&8hBtk8Jmf  }(C~DoAHjڭ \WEh+z`*]ښ6w2% tsٗs7\f%7 ?h9QyQyD$d)q{TQ힗Am~FwO\_*rz@u~.ˍSy=)鍈Pm~Fmܤ\S"q}kvwSe'nzq-=.֥GJP_Kס`(t$IZFO:NKF R*dɪO3YR3S8#@󜈤 ?{gH9 8s$,Y҇8C{v BzPۇ.6Is * āiQ;Hb VI 6LSiR4)aDnCR~Gb5$h*CV*ޫzyn\mC:fkrq0} _. Pc]sVmpd:v{'avXOÅ՟G 0+ߞy5 d˽_G  |Sz>Y ެ#asVά]`5{Fb/~d$`ǝ/skاT&Rnx$bStfgC\_ٛض^h)ulYq]pcUw?~TS tQs|T68DT5#UQ"Z|_͔xY[=kwÔ;rN_r%+?iN2U!P&X{jNT S*`业MM fLZqE+;f?Ipdc|csOi| J9.ʴ 3=01T B!0L@ z db;Us4ʛiCݺiW7<\bd6-`¶X@yQ$+^#SJ^_Ra]cBtP'ډfc""r'HLi$k(?rW`Z[Hk鵠>0zkY]eNFu/Hٟ 5oLAk~^,y__I{k .r;8欌۸9̶ ׀?ǮI.`x]o+;6o^7ꚳ2n4 Jc"J$(FJr/%RDP̿<% zp&EEr8cv;\5gƒ,\/pX#Nw@'6e9@|e  Ufa1Xwuө'zXֶk=qPO!iFD-FN$fU"`k6&|ڮn2ntOy LP'ϑ<9:ߘ'(htO}3w+xd7 Ǧs[ɤ tAwsi8%jeOD IfS S6Mq>яP*ВHj4K_&{ϸ)FrPʋ8*lNb/Q/S֖}qÂ)\%ؼv\g9C%vcFY`ӏ'%(A_$ܴpD*aU2")l&?b\5NVCi'߼f.otFs|"ͣ.Nj6fw`} +߷k}? wm 2*{yEvlw Ћ6ak`:ld[3 Dh0'(\w\故vaۅ/_܍2 ޘА^JDD%fcj6x3.;q"`WsWm`_zSu`S~ ϙa,uߘ "ݔ&Rqr/h86ӥ*&%Wɪ`u=xLp q)lT]ӯX⪸ML%+_S]+X)jXWS)+lZQ*_ͫTJ, 3z@F3Uԡ3]qԝF3eQԙϜPW _m+\G ^F肨 /wV_437wnLMCRں94437Fk4OMC?sЯLQ/Toiaő͛sJJՁ : *L9ܓ<@`n.zi.o<s\DmG<|' +蕦XG<M=p(QEiJd?Q:̿T)`[g|k҄H~ʂIbP" 9% jxTrQ$i )IХA]|Q U38j)Z{m&pwϢC[S!'p͜;{;oMvw؅wz}7a`7So[vam87^&;~>ʸCb}39^mx'۔ע]|;pH @Wv \[QcIXͅ,˗pE-.n\XŎu/;_VO1=(v ;X2 ~҇iOV_Ým;h,/9|a+ kz+Dcُ[=ǯPF$$i XYi(iE Z.fIlVMJ3`Kmq[3Z N~2I`eCĬ>/s zٰpPfLE"Ae.agHv,kqNːߚCᠴm0XU)aobեw.9c[q$z3рL󣩘?S||FʼnF=| 1? Qt(6S^UB0pM=(c(Nt?Nqr)ȝX/9‰4LNyC]oJW~DaxM䋑Olihǝ2FMQ9~UN˷We*:IDAT}dܥnc}IZ+]I*>TޟpEDZ;9N@kZVlcԉ样us{=)Z |kFL<~mWFkc"3Dֵˢ_437 MC?scM5:&h؟1!と.4bgθ1 ̍y3ńPͧk~D6RQ_U:W\^"/~AC?ss)wK gX`DxxDH%nѼXTiρpɀJ jOQd#0*p ɡ#2yf8'\j>xhiH9k /D>rPؘdl"H/$q Yu*2ȄAUzgRRe,M+%oo"}\m+O@+[kAǵ}@nW}ht8=J!?e $ LnٓC"wjGQE69 Ȗ)9,F haxzh=?N8Ql&fQ:Fh(ESQ"9" )-).S"N$'QH{>A4~JG 2Ѽ3/1YD{[S73|^[`kmYF6kvrC60 %lVGGad[ 8 rw[۳l鴏ٮ ߚd>ϣ]puhd+gperH_H#قȃ {0؋garI @-eB5̅l{ef0 3; =hm03b i&iLAR>R>$M*)wΩRuN:3*̆sO;zލvE ܳ "pr3vȻ]b뜵R_ OM@9P`lRG0> נ4.Gt ȁN(ʄ,xk~%e\Yv)yXrL~0^_sOK.WuE~]JiZH61bY!jKIyUD$' Ov9[\ ܆='۞{"P(LP_ (\x)Uxp)}ƿxy;h[u.sSܕ7jʬ{?10u&ܷP1aln-0bs{p FXl ۹& թN;Jszrg]UKlS-Sg}[@Y9.kGhO.![鲺YsFDx2Ւdϐ\i?R2v о)!R)lɡlаJU? 7 h} _ XXT + @*E~dʼn.KYhr8 {ޗF-Y&&eru<8X0auy]-"U(HgCqLw2Aѥ-֨;Ϭ:< 2v$yxB܄yh$ )묭)p6~NtZ >`A[;^Z2u5Fß%I$`] HXѥRBynp @6z{_ll (@` $;(.fwC)VlwySź @<@[S: H%JJ"UyHTC,rD%Tz_[a[gF7gC/)Ux @EtG馧#0[Z?.wSSce)K{JH',O&v;Gʾ}nat>@6})y5mTqMG@I;guӟKع/b>klLglLglLglZոϤZLglLglLglLglLglLglLglLglZ3oWIk3ӟ1ӟ1ӟ1ӟ1ӟ1ӟ?\ mW+r7 6~4\.4\.ϠH۫hh=3A#2g$Fg5ϟQ !SOF0kuQo-mj \Fei4rr[*3QZ`d4_lL4Fk M@ciﯹ y}5u? ^{u? ^{;6؆u`Z˞(W{`];}cgs|Ns9)̙ᯥ&Vm@AEp5EKi46vgmpۅШzVIڊT ΗIr|+z1{evw) Ӌ*f"\7;ct ػ;w7Ҍd+D=/c]靝Jkkkc9YRy\*@PR @FHҩXY'<ITP5PJ"O]TI}6@#߼a ɤ$Cb>|Z"J$U1Tb>(.-DHzT꯭U:MD3Ggw!m"}*BiZJ-pm2` ɇ+5xƖ =%SK& |#pD}=˦t&Ϭ 5 [1ՂNT'?t[mߔ}#UaqTLݙ{ÅQXɖH#ՃY~d!҆w-`QmgC`ZSv~G8Թ $T-4_TvFNKО:;d82OA{!hV <3Lk<6|Տρ(Gֈg(yqc~@`y{Ηw&*R7=.4a -P";,x8xIBOI\EOxnD?&4PW8 A5 SBSӬQF đɃzRvtUxS;u{r=q\t|[ OXܝP@]nEQmXS^{& Pj6j:PI)W|t#$ ʩVЎ7}OhYqq[ vcޅw5<6cl=H\J ǟ `+%6`!e@8G}C$f<'axAAi3}a: 5!+Ы_ Y=Ro"9A%_+׶w{RWt%2 %ѭ5\I ύey DNI…Y!DGq 31H/ϟʪw#) }ro<-To$C}l`ړJ•Cq}wA^\{d }/7*=&K9Xl1?[.OcH3Ƙؔ7T_JsID|WC 8=_g{[6'g>?{Fо <]χ?7Ou}@iRϟ1VRt}v2p! 3liR:HFT !?;趤~[̍)_+]SZ浤E\ؘؘؘؘؘؘؘؘQKּ sKIENDB`Oh+'0d   , 8DLT\ssChenzhong Wanghen Normal.dotaChenzhong Wang2enMicrosoft Word 8.0@@@@@՜.+,D՜.+,, hp|   j  Title 6> _PID_GUIDAN{F358DF13-0230-11D3-9F7D-96C32A000000}    !#$%&'()+,-./01 [(@(NormalCJmH <A@<Default Paragraph Font  l,b$b|XF™  @n(  6   AB S  ?  t@_p@GTimes New Roman5Symbol3& Arial"h$5F$5F!r0 Preferred CustomerPreferred Customer՜.+,D՜.+,\Y bjbjWW ==] YYYmoooooo$^RrY7"YYYmMmmmY mYmmmmm m~c m  jUmHN N!"#!$!%n b|XF™PNG  IHDRhPgAMAPLTEU$$U$$IIUIImmUmmUUU۪U$$U$$$$$$U$$$$$I$IU$I$I$m$mU$m$m$$U$$$$U$$$$U$۪$$$U$$IIUIII$I$UI$I$IIIIUIIIIImImUImImIIUIIIIUIIIIUI۪IIIUIImmUmmm$m$Um$m$mImIUmImImmmmUmmmmmmUmmmmUmmmmUm۪mmmUmmU$$U$$IIUIImmUmmUUU۪UU$$U$$IIUIImmUmmUUU۪UU$$U$$IIUIImmUmmےےUےے۶۶U۶۶U۪UU$$U$$IIUIImmUmmUUU۪Un. pHYs| 9IDATx흋 }\&KɊg2bК>\& .9h#9h#9h#mǿufMtrKȇwfԯ&RnB~-h Լp'ql@t9=_iW^Ǧ=oRACB#}E)X[@! єr3P?Wqe:h)0ؒStAVƄ ?+)|·z5q3kйF'T\yxBu$xhseqz+SƹeErZ6!)K91?::3f逋 +2KptKÊ| c8\dVFo-᪵]Rs$p;e:9+,do} R@GIW=뭯&ZELfW瘿 Z2)@K%pvӒ/:;K6=YC@Afj:ĄA]RhYf_ڑ^3k>~twfަ] ] V͕3:6A+ Z]\,D2E>%9h2n z)hëM@oCQslb7PFm~ I=iO=O*8A@~F'Wp7h y"z`:'`$8'*@ \0JGajJe5}VU~8~o†P1.WFet5hFq!Fwc,z`5Ѥ 5?λRro(qw`MzN)io27 w~^oZw-,e{Ewo $0e+~6c9FEUA0zʂX/5[6!п7_ E ]7 UWF!! +PjЭ!t, s+rY4@7聁цH7x05gF"@]YС˪ϗBU>ŠS ;Alj4uQ$0gPIkTN;De0dWX4| Hہ PtUt9="/H7e=/ݙsk]tz \j*N;;?4\*Џ{5M/ K!ct-h&@CZ4b֗v@@yȗz[@a:4G| "YJwVkAsQ*!'mLk@ɷ)IjAfEr ZTB+~"[_@b$c֌/^y<}}3:}al&mqӻApZ_>:fo@H@tUN Ё2b8%GVajmr-й6i!j>s@\-2r`=MoL<tȿb` ԅY R=heS'뫏04 :YjCϮ+.A}+fаSZ>izаIZi,g@ߝ=F}cZ 4ֿܑ }Z o4XnZSii`֏*?Z㥠MAGNjQ;z-k @Jh]Z? n 1_Aw5Ljuēi]P>~M|o B4ھeG)!m%htP3ׂdd[GHW&A\#AFOoTtR [|m2$j5l)irпwy/u uJtoҁ Z̘]GlU#uI|d _PID_GUIDAN{0906C382-0271-11D3-B396-00A0C9DC9A88}Root Entry FCompObjjOle 1TableZTData /RSummaryInformation(WordDocument2PObjectPool_2147483647  F_2147483646  FOle  1Table CompObj hObjInfo OCXNAMEcontentsObjectPoolWordDocument>SummaryInformation(DocumentSummaryInformation81TableCompObjhObjInfoOCXNAMEcontentsObjectPoolWordDocument SummaryInformation(DocumentSummaryInformation8"DocumentSummaryInformation8t