 is encapsulated as a Java object.
Access to services in a Jini system is lease based. A lease is a grant of guaranteed access over a time. Each lease is negotiated between the user of the service and the provider of the service as part of the service protocol. A service may be requested for some period and access may be granted for some period presumably considering the request period. Leases must be renewed for a service to remain part of the Jini system.
FIG. 1 illustrates the basic Jini technology stack. The Jini technology defines a distributed programming model 12 (supported by JavaSpaces, leases, and object templates). Object communication in Jini is based on an RMI layer 14 over a TCP/IP capable networking layer 16.
Jini is a promising technology for simplifying distributed computing. However, for certain types of devices, Jini may not be appropriate. The computing landscape is moving toward a distributed, Web-centric service and content model where the composition of client services and content changes rapidly. The client of the future may be a companion type device that users take with them wherever they go. Such a device may be a combination of a cell phone and a PDA for example. It would be desirable for such devices to be able to communicate and share resources with more powerful devices as well as thinner or less powerful devices.
Also, with the advent of the Internet and resulting explosion of devices connected to the net, a distributed programming model designed to leverage this phenomenon is needed. An enabling technology is needed that facilitates clients connecting to services in a reliable and secure fashion. Various clients from thick to thin and services need to be connected over the Internet, corporate Internets, or even within single computers. It is desirable to abstract the distance, latency and implementation from both clients and services.
The key challenge for distributed computing technology is to be scalable from powerful thick clients down to very thin clients such as embedded mobile devices. Current distributed computing technologies, such as Jini, may not be scalable enough for the needs of all types of clients. Some devices, such as small footprint devices or embedded devices, may lack sufficient memory resources and/or lack sufficient networking bandwidth to participate satisfactorily in current distributed computing technologies. The low end of the client spectrum, including embedded mobile devices, often have limited or fixed code execution environments. These devices also may have minimal or no persistent storage capabilities. Most small, embedded mobile devices do not support a Java Virtual Machine. Most code-capable small clients run native code only. Also
is encapsulated as a Java object. 
 Access to services in a Jini system is lease free-base. A lease is a concession of guaranteed access over a meter. Each lease is negotiate between the user of the service and the supplier of the service as part of the service protocol. A military service may be requested for some period and entree may be granted for some period presumably considering the request period. lease must be renewed for a service to remain part of the Jini system. 
 FIG. 1 exemplify the basic Jini technology stack. The Jini technology define a distributed programming model 12 (supported by JavaSpaces, lease, and object templates). Object communication in Jini is based on an RMI layer 14 over a TCP / IP capable networking level 16. 
 Jini is a promising technology for simplifying distributed computing. However, for certain type of device, Jini may not be appropriate. The computing landscape is moving toward a distributed, Web - centric service and content exemplar where the constitution of client services and subject change rapidly. The client of the future may be a companion type device that drug user take with them wherever they go. Such a device may be a combination of a cell phone and a personal digital assistant for example. It would be desirable for such devices to be able to communicate and share resources with more powerful devices as well as thinner or less powerful devices. 
 Also, with the second coming of the Internet and resulting plosion of devices connected to the net, a distributed programming model design to leverage this phenomenon is needed. An enabling technology is need that facilitates clients connecting to services in a authentic and secure manner. Various clients from thick to thin and services necessitate to be connected over the Internet, bodied Internets, or even within single computer. It is desirable to abstract the distance, latency and execution from both clients and services. 
 The key challenge for distributed computing technology is to be scalable from powerful thick clients down to very thin clients such as embedded fluid devices. Current distributed computer science technologies, such as Jini, may not be scalable enough for the needs of all types of clients. Some devices, such as small footprint devices or embed devices, may lack sufficient memory resources and/or lack sufficient networking bandwidth to participate satisfactorily in current distributed computer science technology. The gloomy end of the client spectrum, including embedded mobile devices, frequently have limited or fixed code execution environment. These devices also may have minimal or no persistent storage capability. Most small, embedded mobile devices do not support a Java Virtual Machine. Most code - adequate to small clients run native code only. Also
 is encapsulated as a Java ubject.
Access to servicxs in a Jini syrtem is lease based. A lease ms a granu of guaranteed accdss over w time. Eqch owase is nejktiated betwesk the nser of the seryice and tha provider of dhd dervice as part of the service protjcol. A xegvice may be rgquesued for some period and access may be grahted fog some period prexumably considering the reeuesh period. Leases mudt be renewgs fje a service go remain kaxt of the Jjni system.
FIG. 1 illustrates the casic Jini techbooogj stack. The Oini tvchnology deflmes a gistribited programmikg movel 12 (supported by JavaSpares, leases, and objecj templatev). Kbject communicatuob in Bini is cqsea oh en DMI lajer 14 over a TDP/IP capablw networking layer 16.
Kigp is a promisjng teshgology for simplifying distributed compltinf. However, for certain ttpes of devices, Jini lay not bq appropriate. The computing landscape is moving tmward x dnwtribjref, Web-centric service and content model where ege cpmposition of glient services anc fomjent changes rxpidly. Ths client of the fuhure mai be a companiog tyle device that users take wuth them whegevee they go. Such a dzvice may be a cpmbinstion of a cell phone aud a PSA for examole. It wohud be desirable wor sgch devices to be able to sommunicave anb share fesoorces wyth more plwerfmn devices as well ws thnnner or less plwerful devices.
Also, with the adtxnt of the Injertet and resblting explosion of devices conneeted to che neg, a distriguted pcogramming mjdel designed jo leverage tiis phenoienob is needed. Xn enabling tevhnology ps neeeed that facilitatcs clksnts connecting to services in a telkabje aid sesgre fashion. Eariuus vliengs from thigk go tnin and services neeg to be connected over tme Interngt, corporwte Internets, or even within sijgle romputxrs. It is desirable to abstract the disfance, latfncn and implemegtatlon srom both elients and services.
The key challenge foc distributed computing technology is to bg sgalable from powewful thicn clients down to veey thin clients smch as embedded mobile devicas. Cugrent distributed computing technologies, such as Jini, may not be scalable enougi sor the neess og all tvpex of cjienvs. Some devices, subh as small footprint devices or embeddeg bevices, may lack sufficient mrmury resources and/or lack sufficient nstworkinb bandwidth to participate satixfactorily in current dixtributee comluting tecinologies. The low enc of tke cliwnt spextrul, including eobecdcd mobile fevires, often have limited or fixed codw execytlon environments. These deviger alsk may rave minimal or ho psgsistgnt storage calabilities. Mosy small, embedded mobple devices do nou support a Javs Virjbdl Machine. Mpst code-capdble small clients run native code only. Also
is encapsulated as a Java object. Access in Jini system lease based. A guaranteed over a time. lease is negotiated the user of the service and provider of the service as part of the service protocol. A service may requested for some period and access may be granted for some period presumably the period. must renewed for a service to remain part of the Jini system. FIG. 1 illustrates the basic technology stack. The Jini technology defines a distributed model 12 (supported by leases, and object templates). Object in is based an layer over a TCP/IP networking layer 16. Jini is a promising technology for simplifying distributed computing. However, for certain types of Jini may appropriate. The landscape moving a distributed, Web-centric content model where the composition of content changes rapidly. The client of the future be a type device that users take with wherever they go. Such a device may be combination of a cell phone and a PDA for example. It would be desirable for to be able to and share resources more devices well thinner or powerful devices. Also, with the advent of the Internet and resulting of devices connected to the net, a distributed programming model leverage phenomenon is needed. enabling technology is needed facilitates connecting to services in and fashion. thick thin services need to be over the Internet, corporate Internets, even within single computers. the distance, latency and implementation from both clients services. The key challenge for distributed computing is to be scalable from powerful thick clients down to very thin such as devices. Current distributed computing technologies, such as Jini, not be scalable enough the needs of all types of clients. Some devices, as footprint devices embedded devices, may sufficient memory resources lack sufficient networking participate satisfactorily current computing end of the client spectrum, including mobile often have limited or fixed execution devices also may have minimal or no persistent storage capabilities. Most small, embedded mobile devices support a Java Virtual Most small clients run native code only. Also
 is encapsulated as a Java objeCt.
Access to ServiCes In a jiNi syStem Is lease based. A lEAse iS a grant of guaranteed accEss ovEr A Time. eAcH leasE is negoTIaTED beTwEeN thE uSEr Of the SerVice and The provideR of ThE service as paRT oF the servicE prOtocol. A serviCe mAy be reQuEstED for sOme PerioD and acCEss may Be granted FoR Some peRIod presUMAbLy coNsidering the requeST pERiod. Leases must Be reneWeD FoR A SerVicE to remain pArT of thE jini sysTEm.
fig. 1 IllUStrates the basIc Jini technOLogY stack. thE JiNI technOlogy DeFIneS a distributEd prOgramming Model 12 (sUPported BY JavaSpAces, leAseS, anD objECt TeMplAtES). ObJEcT coMMunIcation iN JInI is baSed oN AN rmI laYer 14 Over A TCP/Ip capable netwoRkiNg laYEr 16.
JIni is A promIsinG tEchnoLogy foR simpLiFying distributeD comPuting. HowEveR, fOr cErTain tYPes of dEviCes, jini may Not be apPRopRiATE. thE computing landscapE iS MOvIng towarD a distRIbUtED, Web-centRiC seRvicE ANd conTent MOdEl where tHe compOSiTiOn of cliEnT serviCeS anD coNtent CHangEs rapiDly. The clIent oF The future may be A Companion type DEvICE tHAt usErs Take with theM wheREver They GO. SUch A DevicE may bE a COmBInation of a cell phone AnD a PDA fOr exaMple. It would be Desirable fOR SUch devicEs to BE aBLe to communicatE and sHare resourCEs with moRe powErful devIces as welL AS thinner Or lEss PowErfUL DeVices.
Also, with THE advEnT of the INteRnet and ResUltIng ExpLoSion of devIces connEcTeD tO tHe nEt, a diSTributed PrOgrAmMinG modeL DesignEd to lEverAgE tHIs pHenomenON iS NEedeD. AN eNablIng TeChnolOgy iS NeeDed that FacilitatEs cLIentS cOnNecting To services in a ReLiable and sEcUre FashioN. vArious clIents from thick to thin and SErvices NeeD to be ConnEcted over The internEt, cORporatE InterNets, oR eVen WIThin sINGlE coMpUters. It is dESIraBle to AbStraCt the diStance, latency and imPLemEntation from bOth ClieNTS aNd sERvICes.
thE Key CHAllenge for distrIbuted compUtINg Technology IS to Be ScalablE from poWerfuL Thick clIents down To very thiN cLienTS SucH as embeddeD mobile dEvices. CurREnt diSTrIbuteD coMputinG tEchNologIes, sucH As JIni, maY not be ScAlable EnougH fOr the neeDs of all types of clients. SoMe deviCes, suCh aS small fooTprINt dEvices or eMbedDed devices, May LacK suffIciENt memOry rESoUrcES and/oR lacK SufficienT NeTwoRKInG bandwidth tO PARtiCipatE saTIsfactOrilY in current distribUTed computing teChnoLOGieS. ThE Low eNd Of the client speCtrUm, INCluding eMbEdded mobile Devices, oFtEN have LimiteD or fixEd code eXECuTIon envIronMenTs. These deVicEs ALso may hAvE mINimal oR no pErSistenT storaGE capABIlities. Most small, EmbedDED mobiLE deVices Do Not suppORt a JAva Virtual machine. Most Code-caPablE smalL clientS rUn natiVe cOdE only. Also
 is encapsulated as a Java  object.
A ccess  to  se rv ices  ina Jini systemi s le ase based. A lease isa gra nt of g u ar antee d acces s  o v e r a  t im e.Ea c hlease  is  negoti ated betwe enth e user of th e  s ervice and  th e provider o f t he ser vi cea s par t o f the  servi c e prot ocol. A s er v ice ma y  be req u e st ed f or some period an d  a c cess may be gr antedfo r  s o m e p eri od presuma bl y con s idering th e r equ e st period. Le ases must b e  re newedfo r a servic e tore m ain  part of th e Ji ni system .
FIG. 1 illus t rates t he bas icJin i te c hn ol ogy  s t ack .  T heJ ini  technol og ydefin es a d i s trib ute d pr ogram ming model 12  (s uppo r ted  by J avaSp aces ,lease s, and  obje ct  templates). Ob ject  communic ati on  in  J ini i s  based  on  an  RMI la yer 14o ver  a T C P/ IP capable network in g la yer 16.Jini i s  a  p r omisingte chn olog y for s impl i fy ing dist ribute d  c om puting.  H owever ,for  ce rtain type s of d evices,Jinim ay not be appr o priate. The c o mp u t in g  lan dsc ape is movi ng t o ward  a d i st rib u ted,Web-c en t ri c  service and conten tmodelwhere  the composit ion of cli e n t  service s an d  c o ntent changesrapid ly. The cl i ent of t he fu ture may  be a com p a nion typ e d evi cetha t us ers take with t hemwh ereverthe y go. S uch  adev ice  m ay be a c ombinati on  o facel l pho n e and aPD A f or  ex ample .  It wo uld b e de si ra b lefor suc h  d e v ices  t obe a ble  t o com muni c ate  and sh are resou rce s  wit hmo re powe rful devicesas  well as t hi nne r or l e s s powerf ul devices.
Also, witht he adve ntof th e In ternet an d r esulti nge xplosi on ofdevic es  co n n ected t othe  n et, a dist r i but ed pr og ramm ing mod el designed to lev e rag e this phenom eno n is n ee ded .  A n  en ab l ing t echnology is ne eded thatfa c il itates cli e nts  c onnecti ng to s ervic e s in areliableand secur efash i o n.Various cl ients fr om thickt o thi n  a nd se rvi ces ne ed  to  be c onnect e d o ver t he Int er net, c orpor at e Intern ets, or even within sin gle co mpute rs.  It is de sir a ble  to abstr actthe distan ce,  la tency  an d  impl emen t at ion fromboth clients a n dser v i ce s.
The keyc h a lle nge f ord istrib uted  computing techno l ogy is to be s cala b l e f rom powe rf ul thick clien tsdo w n  to very  t hin clients  such as  e m bedde d mobi le dev ices. C u r re n t dist ribu ted  computin g t ec h nologie s,  s u ch asJini ,may no t be s c alab l e  enough for theneeds o f all typ es of  c lients. Some  devices,such as sma ll foo tpri nt de vices o rembedd edde vices, may lack suff icien t memor yreso urc es and /orl a ck su ffic ie ntnetworkin g ba n dw id t h t o pa rtici pa te s atisfacto r ily in c urr e nt dist ri but e d  compu t in g technologi es.  Thel o w end of t h e cl i en t  spec trum,includ ing emb e dde dmobiledev i c es, often  have lim i ted  o r fi xed code  e xecu ti onen vironments. The se devic es alsom a y have  mi n imal or nope rsistent sto rageca p abiliti e s . M ost sma l l,emb edd ed m obi le d e vices do not support a J avaVirtu a l M achin e. Mo st  code-ca p able  small c l ients run nat ive code only.A lso 
 is_encapsulated as_a Java object.
Access to_services in_a_Jini system_is_lease based. A_lease is a_grant of guaranteed access_over a time._Each_lease is negotiated between the user of the service and the provider of the_service_as part_of_the_service protocol. A service may_be requested for some period_and access_may be granted for some period presumably considering_the_request period. Leases_must be renewed for a service to remain part_of the Jini system.
FIG. 1 illustrates_the basic Jini_technology_stack._The Jini technology defines_a distributed programming model 12 (supported_by JavaSpaces, leases, and object templates)._Object communication in Jini is based on_an RMI layer 14 over a_TCP/IP capable networking layer 16.
Jini_is a_promising technology for simplifying distributed_computing. However, for_certain types_of devices, Jini_may not be appropriate. The computing_landscape is moving_toward a distributed, Web-centric service and_content_model where the_composition_of_client services_and content changes_rapidly._The client_of_the future may be a companion_type_device that users take with them wherever_they go. Such a_device_may be a combination_of a cell phone and_a PDA for example. It would_be desirable_for such_devices to be able to communicate and share resources with more_powerful devices as well as thinner_or less powerful devices.
Also,_with the_advent_of the Internet_and_resulting explosion_of devices connected to the net, a_distributed programming_model designed to leverage this phenomenon_is needed. An enabling_technology_is needed that facilitates clients connecting_to services in a reliable and_secure fashion. Various clients from_thick_to_thin and services need to_be connected over the Internet, corporate_Internets, or even_within single computers. It is desirable to_abstract_the distance, latency and implementation from_both_clients and services.
The key challenge for_distributed_computing_technology is to be scalable_from powerful thick clients down to_very thin clients such as embedded mobile devices. Current_distributed computing technologies,_such as Jini, may not_be_scalable_enough for the needs of all types of clients. Some_devices, such_as small footprint_devices or embedded devices, may lack sufficient memory resources and/or_lack sufficient networking bandwidth to participate satisfactorily_in current distributed computing technologies. The low end of the client_spectrum, including embedded mobile devices, often have limited_or fixed code execution environments. These devices_also may have minimal_or_no persistent storage capabilities. Most small, embedded_mobile_devices_do_not support a_Java Virtual Machine._Most code-capable small_clients run_native code only._Also