General Question about RMI

Okay here is what I am trying to do:
I work for a small consulting firm and part of what we do is we process a tremendous amount of data using a suite of tools written in C/C++. We have a Java application which is really just a script (Written in standard Java) that makes a whole bunch of system calls, namely the commands in the suite of tools written in C. What we want to do is, is over our network, farm some of these system calls (or maybe even just CPU cycles) to multiple machines with the same suite of tools on them. Is this possible/plausible using RMI? Is there something that would be better for it? We have plenty of bandwidth across our network and most of the data is stored on a 15+ TB SAN.
Also any books on the subject that you could recommend would be very helpful as well :)
Any help would be very much appreciated.

ofcourse passing over socket is always an option. Sure in that case you will have to serialize the object yourself or make a mini-protocol of some kind.
In our project we also use XML to pass object between C++ and Java world, instead of using CORBA.

Similar Messages

General question about iTunes Match and multiple libraries

Hello to everyone,
I have a general question about the iTunes Match service, which is available since yesterday in my country (Italy). Currently my library situation is the following:
Computer A (desktop, Windows 7): "big" iTunes library (about 20 GB), at the moment not associated with my Apple ID
Computer B (MacBook Air 2011): "small" iTunes library (about 5 GB), associated with my Apple ID
At the moment, both my iOS devices (iPhone 4 and iPad 2) are synchronized with the smaller library on the MacBook Air.
Question is as follows: should I subscribe to iTunes Match, would it be possible to upload the "big" library (provided I associate it with my Apple ID) to iCloud while keeping my devices synchronized with the "small" one?
Ideally, at the end of the day, the situation should be the following: both iOS devices with music from the small library + possibility of downloading songs from iCloud (coming from the big one). Is this possible?
Maybe the question sounds stupid, but I want to be sure about this before paying for the service.
Thanks a lot.

Yes, you could also associate your larger library with iTunes match if you associated your Apple ID with it. However any purchases in the library made from another Apple ID will not be matched with iTunes much.
If both libraries are part of iTunes match, then all your devices will see all of the content from both libraries, which content you choose to have on those devices and which you have accessible via iTunes match is entirely up to you.

Newbie question - general question about e-mail sync

Hi,
I have a general question about email sync and BlackBerry smartphones. Are there any devices that allow email syncing with a Microsoft Exchange 2007 system that do not require the BlackBerry Enterprise server?
Thanks; sorry if this has been asked before but I was unable to find it in the forums, documentation, etc. Everything I found assumes that for this kind of environment you will be using a BlackBerry Enterprise solution, but I can't assume.
Thanks again.
Solved!
Go to Solution.

Hi and Welcome to the Forums!
If the Exchange server has anything that faces the internet (OWA, POP, IMAP), then BIS can be used to handle email (only email...calendar and contacts require BES to sync OTA).
Or, a PC, inside the network (but with an internet path) and logged into the email server (using Outlook), can be left running, using the RIM Desktop Software's Desktop Redirector capability to forward messages to the BB.
Those are basically the options.
Hope that helps! Let us know!
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If anyone has been helpful to you, please show your appreciation by clicking the button inside of their post. Please click here and read, along with the threads to which it links, for helpful information to guide you as you proceed. I always recommend that you treat your BlackBerry like any other computing device, including using a regular backup schedule...click here for an article with instructions.
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I hava a question about RMI,please help me!

Ladys and Gentleman,I hava a question about RMI.I wirte four little programs in java that is about RMI on my PC.
import java.rmi.*;
public interface AddServerIntf extends Remote{
double add(double d1,double d2) throws RemoteException;
import java.rmi.*;
import java.rmi.server.*;
public class AddServerImpl extends UnicastRemoteObject implements AddServerIntf{
public AddServerImpl() throws RemoteException{
public double add(double d1,double d2)throws RemoteException{
return d1+d2;
import java.net.*;
import java.rmi.*;
public class AddServer{
public static void main(String args[]){
try{
AddServerImpl addServerImpl=new AddServerImpl();
Naming.rebind("AddServer",addServerImpl);
}catch(Exception e){
e.printStackTrace();
import java.rmi.*;
public class AddClient
     public static void main(String args[]){
     try{
     String addServerURL="rmi://"+args[0]+"/AddServer";
     AddServerIntf addServerIntf=(AddServerIntf) Naming.lookup(addServerURL);
     System.out.println("The first number is: "+args[1]);
     double d1=Double.valueOf(args[1]).doubleValue();
     System.out.println("The second number is: "+args[2]);
     double d2=Double.valueOf(args[2]).doubleValue();
     System.out.print("The sum is: "+addServerIntf.add(d1,d2));
     }catch(Exception e){
     System.out.println("Exception: "+e);
And I compiled these files,so I got 4 class files(AddServer.class,AddServerIntf.class,AddServerImpl.class,AddServerClient.class).Then I use "rmic AddServerImpl" got another two files(AddServerImpl_Skel.class and AddServerImpl_Stub.class).Then I input command:rmiregistry,in another window,I input command:java AddServer,I got some exceptions,I was confused by these exceptions.The exception is:
D:\MyJava\rmi_3>java AddServer
java.rmi.ServerException: RemoteException occurred in server thread; nested exception is:
java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is:
java.lang.ClassNotFoundException: AddServerImpl_Stub
java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is:
java.lang.ClassNotFoundException: AddServerImpl_Stub
java.lang.ClassNotFoundException: AddServerImpl_Stub
at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(Unknown Source)
at sun.rmi.transport.StreamRemoteCall.executeCall(Unknown Source)
at sun.rmi.server.UnicastRef.invoke(Unknown Source)
at sun.rmi.registry.RegistryImpl_Stub.rebind(Unknown Source)
at java.rmi.Naming.rebind(Unknown Source)
at AddServer.main(AddServer.java:8)
But some times this exception will not appeared.Who can give me answer or suggestion,thanks a lot.
By the way,when I run shutdown.bat in tomcat_root\bin,I can get some exceptions:
C:\Tomcat\bin>shutdown
Using CATALINA_BASE: ..
Using CATALINA_HOME: ..
Using CATALINA_TMPDIR: ..\temp
Using JAVA_HOME: C:\JDK
Catalina.stop: java.net.ConnectException: Connection refused: connect
java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:350)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:137)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:124)
at java.net.Socket.<init>(Socket.java:268)
at java.net.Socket.<init>(Socket.java:95)
at org.apache.catalina.startup.Catalina.stop(Catalina.java:579)
at org.apache.catalina.startup.Catalina.execute(Catalina.java:402)
at org.apache.catalina.startup.Catalina.process(Catalina.java:180)
at java.lang.reflect.Method.invoke(Native Method)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:203)
I use Windows server 2000+JDK 1.3.1_04+tomcat 4.1.7

Maybe I am off base here but it seems to me the problem is the way in which you bind your server. The server must be bound to the same address and you are looking up from, i.e. "rmi://" host "/AddServer"
so
Naming.rebind("AddServer",addServerImpl);should be
Naming.rebind("rmi://127.0.0.1/AddServer", addServerImpl);to match
String addServerURL="rmi://"+args[0]+"/AddServer";
AddServerIntf addServerIntf=(AddServerIntf)
Naming.lookup(addServerURL);Hopefully this will solve your problem, if not it is a problem with your classpath. An easy way to make sure it can see your files is to set the java.rmi.server.codebase to point to where your classes are, e.g.
java -Djava.rmi.server.codebase=file:"c:\\cygwin\\home\\tweak\\keck_folder\\cmsi401\\RMIGalaxySleuth\\classes\\" AddServer
I had to set the codebas for my rmi stuff to work no matter how much I messed with the classpath.
Hope this helps,
Will

General Question about SAP Documentation. Where to find?

Hello,
I am relatively new in the SAP business and so I have some general questions about the SAP Documentation.
Often internet-links like
http://help.sap.com/printdocu/core/Print46c/en/data/pdf/FIBP/FI-AP-AP-PT.pdf
are posted here by group members.
But where do these group members find these documents?
All I can see at help.sap.com is IDES (the model company created by SAP)and the WWW-version of the SAP-Bibliothek.
Were can I find these PDF-Files?
I would appreciate any hint and tip!
Thank you!
Kakue

thats true! i dont know how to find either. Everytime i need something i ask on the forum.
Here's a good link
http://www.easymarketplace.de/online-pdfs.php
Plz reward points if helpfull

General Questions about BI

Hello,
I want to get into SAP BI and have some questions about it.
Is there a big downside in installing only the BI components without the Java BI components, or is it even possible if you want to work with BI. What are the general differences between BI and Java BI?
I think the main aspects i will work with will be data warehousing and some basic reporting.
The reason why i'm asking is that i want to run the BI components in the same system as the ECC Server (its just a test system). I read that the Java BI component needs EPC and EP and that would probably be too much for a single system (6 GB RAM).
Thanks a lot in advance,
Martin

Thanks for your hints, they were really helpful.
As i mentioned i mainly want to work with the general Data Warehouse and Reporting capabilities, so i think it should be okay.
Actually i'm planing to write about BI and SAP within my master thesis.
Another question, what will be with SAP BI in the future regarding the Business Object acquisition? Is there still any point in learning SAP BI or will SAP BI disapear in the future? I heard that the basic BI functionality (e.g. Datawarehouse ) will still be used but the reporting capabilities would be disappear. I'm not sure if that is right and i'm really new to this topic. So any comments are welcome.
Thanks,
Martin

Some basic questions about rmi registry context "bind" and "lookup"

We have more processing to do than can be accomplished with a single computer. To solve the problem I've implemented a distributed computing solution using RMI. (The first time I saw RMI was about 2 weeks ago, so please bear with me!)
The implementation is a proof of concept not a fully fleshed out system. I have one "Workunit Distributor" computer and any number of "Data Processor" computers all on the same lan segment. "Workunit Distributor" and "Data Processor" computers are both RMI client and server to each other. The "Data Processor" computers are given the ip address and name of the "Data Distributor" on the commandline when they start. They communicate their willingness to receive and process a workunit to the ""Workunit Distributor" via a RMI call. Work units are sent to available "DataProcessors" and results are eventually returned to the "WorkunitDistributor" (minutes or hours later). The model program works quite well, and appears to be capable of doing the processing we need to get done.
But now that it seems viable, I've been asked to make it a little more scalable, flexible and self configuring. In particular, instead of one "Workunit Distributor", any number of "Workunit Distributors" should be allowed to show up or disappear from the lan at any time and the system should continue to function. I've worked out a good scheme for how this can be done, but I have a couple of questions about the RMI registry (registries?). I'm trying to keep from implementing some functionality that may already be available as a library or subsystem.
With my current model design, each computer binds to its own registry with a unique name. For instance:
CRDataProcessorImpl crdpi = new CRDataProcessorImpl(svr);
Context crDataProcessingContext = new InitialContext();
crDataProcessingContext.bind("rmi:"+hostName, crdpi);
Currently the "Data Processors" get the info they need for a Context lookup() of the one and only "Workunit Distributor" from the commandline. And the info the "Workunit Distributor" needs to do a Context lookup() of a "DataProcessor" is passed to it from each "DataProcessor" via a RMI call.
But in the newer (yet to be implemented) scheme where any and all "Workunit Distributors" show up and disappear whenever they feel like, the naming bootstrapping scheme described above won't work.
I can imagine a few ways of solving this problem. For instance, having "Workunit Distributors" multicast their contact information on the lan and have a worker thread on each "Data Processor" keep track of the naming information that was multicast. Another alternative (more organized, but more complex) might be to have a dedicated host with a "well known" address and port that "Workunit Distributors" and "Data Processors" could all go to, to register or look up at an application level. Sort of a "domain name service" for RMI. But both these schemes look like a lot of work to implement , debug and maintain.
The BEST thing would be if there was one plain vanilla RMI registry that was usable by all RMI enabled computers instead of having each computer have its own local name registry. In volume 2 of the Core Java2 book it says that every registry must be local. I'm only hoping there's been progress since the book was published and now a central rmi registry is available.
If you have any ideas about this I'd like to hear what you know.
Thanks in advance for any advice.
Lenny Wintfeld
ps - I don't believe web services, as full featured as it is, is a useful alternative. I'm moving 100's (in the future possibly 1000's) of megabytes back an forth for processing.

The local bind/rebind/unbind restriction is still there and it will always be there.
I would look at
(a) RMI/IIOP, where you use COSNaming as a registry, which doesn't have that registriction, and which also has location-independent object identifiers
(b) Jini.

Asking general questions about 'computing' matters.

Hello
I'm new to the Mac world - I posted my first question on the forums today!
I have reviewed the discussions site - everything seems very specific to apple products. Where, if anywhere, could I post a general question - like this one:-
I have a notion that when one connects to a server directly (Usenet newsgroups for example) one makes a deliberate 'hole' in one's firewall, be it software or simply because one is using a NAT router. Sending messages to and receiving posts from Usenet is far quicker than using email, so I'm fairly confident that this is so.
I am well aware that any URL one visits can instantly determine much information about the connecting machine. (see http://www.browserreport.com/ as an example).
Anti-malware programs can only detect known viruses and spyware - I see no reason at all why, once one has granted a direct connection facility, between a group on a private server to
one's own machine, malware could not relatively simply be injected onto one's computer.
If the malware was currently unknown, how would one ever know?
Thanks in anticipation of a helpful response
David B

HunterBD wrote:
I'm new to the Mac world - I posted my first question on the forums today!
Excellent!
I have reviewed the discussions site - everything seems very specific to apple products. Where, if anywhere, could I post a general question - like this one:-
Unfortunately, not in this forum. This forum is specifically about the discussion forum itself. It is kind of like a meta-forum. Hopefully, the moderators will just move your post somewhere more appropriate. (As indeed they just did!)
I have a notion that when one connects to a server directly (Usenet newsgroups for example) one makes a deliberate 'hole' in one's firewall, be it software or simply because one is using a NAT router.
Kind of and kind of not. Firewalls are greatly misunderstood. But essentially, yes, any internet connection you establish has some risk involved. However, the risk of making an outgoing connection is infinitesimally smaller than setting up a server to let hackers bang on 24x7.
Sending messages to and receiving posts from Usenet is far quicker than using email, so I'm fairly confident that this is so.
Really? I don't think so.
I am well aware that any URL one visits can instantly determine much information about the connecting machine. (see http://www.browserreport.com/ as an example).
Not really. It depends on what you are doing. You always give away your IP address, unless you are behind a proxy. In that case, you give away the proxy's IP address. But the proxy still knows who you really are.
If the protocol in question supports such information, then it can be determined. A web browser does send some information about you, but you can easily change it and masquerade as some other browser. With other protocols, it isn't so easy to tell what kind of OS or software is being used.
Anti-malware programs can only detect known viruses and spyware - I see no reason at all why, once one has granted a direct connection facility, between a group on a private server to
one's own machine, malware could not relatively simply be injected onto one's computer.
If the malware was currently unknown, how would one ever know?
You wouldn't
Don't grant anyone direct connection to your machine.

General question about Mountain Lion

I've kept clear of Lion on both my MACS because of all the "bad press" it got, I'm still running Snow Leopard on my MACS and I've never had a day of problems with either. Also I run Logic Studios on both my MACS and didn't want to chance having issues with interface compatability, lack of drivers and such. My question is kind of simple and for better or worse comes down to opinion, what is the general feeling about Mountain Lion? Is it a big improvement over Lion? Is it more stable with less bugs? Any issues running Logic? I'm "playing with the idea" of upgrading but I want to do my research first. If Mountain Lion is not a big improvement over Lion or if people are having issues with running Logic I'm going to stick with SL.
Thanks for your opinions in advance.

Be cautious about listening too much to replies you're likely to get. These sort of questions in a place like this are like magnets to people who are having problems and want to complain about it. You're likely to hear some horror stories that don't represent the majority of cases.
ML has been excellent so far for me, faster than Lion and no serious bugs I've discovered so far. But if you upgrade, be sure to do your homework: backup, check compatibility of all your software (including things like printer drivers) and repair the hard drive with Disk Utility before installing.

Where to direct a general questions about foreign films subtitles?

I recently purchased a foreign film "Break Ke Badd" from the iTunes store. Although, it didn't specify that it had English subtitles, I assumed it did. After the full download, I tried to watch it and there weren't any English subs. I contacted iTunes and they more than happy to refund the money back to my account. Now after a few weeks, the iTunes store DOES list Eng subs for this film. I don't want to purchase it again and have to contact iTunes for another refund...Therefore my question is, is there a general question contact one could use to find an answer to my question. Basically, to verify that this movie, indeed has English subs before I re-purchase.
Any info is appreciated!

Yes I know as the [https://support.mozilla.org/en-US/questions/ Questions] section is more for desktop Firefox support and the place I linked to is for "Firefox OS" support in English where some who are involved with it do post in it occasionally.
I would have moved that [https://support.mozilla.org/en-US/questions/962783 thread] to the "Firefox OS" English section, however I cannot as the [https://support.mozilla.org//questions/ Questions] and [https://support.mozilla.org/forums Contributor Forums] are not the same.

Round trip workflow with proxies between Premiere and AE / a more general question about how these programs work?

Hi all,
I'm new to editing with proxies in Premiere and have some questions about how to handle the relationship with After Effects. Say I have a rough cut (with proxies) and I want to send it to AE to do some effects. The simplest thing to do seems to be to replace the proxies with the originals in Premiere, send the project to AE and do my thing. But if I then want to send the project back to Premiere, it will involve the original files, which are too machine-intensive for me to edit. In theory, it seems like there should be a way to send the project with original footage to AE, do effects, send it back to Premiere, and then replace it with proxies to do further editing while retaining the effects.
This leads to a confusion about how AE works. When I do an effect, am I correct in assuming that it does nothing to the original file? If that's the case, it seems like it shouldn't matter (in the editing stage) what file AE "applies" an effect to (proxy or original). But I feel like there's a hitch in this workflow. The same question could also be asked about going back and forth in Speed Grade.
Perhaps there is no real answer to this and the best option is to save effects and grading for after I have picture lock, but sometimes that's not entirely possible or convenient, etc.
Hopefully this makes some sense—It's a little hard to explain.
Thanks.

Hi Mark,
Here are the specific sections of the manual that should give you the best explanation regarding the Check out/in workflow for FCP projects in Final Cut Server:
Check out:
http://documentation.apple.com/en/finalcutserver/usermanual/#chapter=7%26section =5
Editing:
http://documentation.apple.com/en/finalcutserver/usermanual/#chapter=7%26section =6
Check in:
http://documentation.apple.com/en/finalcutserver/usermanual/#chapter=7%26section =7
-Daniel

I have a handful of general questions about Firefox OS as a consumer..

I couldn't find a better place to post this, so I'm trying on here.
I'm in the market for a tablet (high-end), and I'm holding off on getting an Android-powered one because of Firefox OS. However, I have some general questions and concerns regarding performance, software and hardware. Here they are.
1. Is the Firefox OS interface as responsive as a native experience on say an iPad or an Android tablet? (Is there any lag on swipes between screens, button presses, etc?) If not, will it be in the future?
2. Will I miss the Android marketplace or the Apple app store, being restricted to only HTML5 apps? Do you think this will become an irrelevant question as the HTML5 app ecosystem grows?
3. Do you think the quality of HTML5 apps will be inferior to those from existing app stores because they are free?
4. Will the Firefox browser be the only one available in Firefox OS? (i.e. will there be the option to use Chrome, Opera or any other browser if the user so wishes?)
5. Will Firefox OS include useful utility apps, such as an alarm clock, a calendar, a weather app, etc?
6. I read a lot, both on the web (news, video game reviews), as well as ebooks. Will Firefox OS on a tablet be a pleasant experience conducive to e-reading? (Will it include a good ebook reader app?)
7. Will there be a high-end Firefox OS tablet that is comparable in specs to the Nexus 10? (i.e. impressive screen resolution, powerful CPU/GPU, lots of inputs/outputs like USB, HDMI, microSD, etc) When do you think such a device might become available?
8. Would it be possible to flash Firefox OS onto say a Nexus 10 or other tablet or phone if one wanted to use it as their OS instead?
Thanks!

1. Depends on the phone but a avererage power android phone would likely cost the same as a high end firefox os phone.
2. HTML 5 is really the future of the web, I've heard that Firefox will let you package apps to be playable offline, but not sure if thats true.
3. I '''think''' Firefox OS may have paid apps that will be restricted to users who buy them.
4. I think Mozilla will be nice enough to let Google and Opera make browsers. Google let Mozilla do that with FF for android.
5. See the simulator https://addons.mozilla.org/en-us/firefox/addon/firefox-os-simulator/
6. too early to say
7. too early to say, but Foxconn (helps apple) makes some apple products, so yes in the future is see a high end Firefox OS tablet 2-3 years down the road.
8. not sure
NOTE: Please note that we are only contributors, we dont develop firefox os.
You can ask more on the IRC channel as there are likely devs there.
https://client00.chat.mibbit.com/?server=irc.mozilla.org

General questions about using webservices and xml as opposed to an oracle driver

Dear Experts; I have a general question which I have yet to test. Is it faster to use an ODBC driver to connect and retrieve data from an Oracle database than creating a .net webservices and using an XML to get the data for your web application. THank you

At some point in the architecture stack some component will need to access the database in order to get the information from the database. That component will need to use an Oracle client driver.

General question about Mac hardware

Hello. I have always used Windows. I am considering picking up a used Macbook. I have some questions about hardware. Chiefly, is there a specific reason that Apple is still dedicated to the Core2Duo processors, even in the highest-end Pros? With the advent of the Intel Core i3, i5 and i7 processors, many PC laptop manufacturers have embraced them, especially the better mainstream manufacturers, like Sony and Toshiba. I know a lot about Windows, but I don't know much about OSX.
Is there something in the software that allows for a Core2Duo on OSX to run as efficiently or more so than an i3 or i5 on Windows 7? As it stands, comparing strict hardware profiles (processors in particular) between what appear to be equivalent current Macbooks and Windows 7 PCs, the Sonys and Toshibas seem to have a distinct advantage.
Sorry if this is a tired question or whatever. Believe me, I'm not asking "WHAT'S BETTER? A MAC OR A PC?" Really.
Many thanks to anyone who can point me to an answer.
Chris

Well, as to if there is anything that makes OS X run better on the C2D rather than a i3 or i5. I have never use an i3 based computer, but the i5 mac I used was very fast (tried the i5 27" iMac). I don't know why they are currently still using the C2D over that. I can say that the i5 didn't feel any faster, even the quad core Mac pro didn't feel faster. The main advantage to more cores will be in doing more at once. This makes the biggest difference is seen when running things like video editors. There is also a lot more to making the computer fast than just the CPU, the chipset, system bus, video card, and hardware controllers all make a huge difference. Apple has always used very good quality hardware, there have even been times where MacBook Pros have been rated as the best laptops to run Windows. But OS X will run faster on the same hardware because it is a more streamlined OS that uses the hardware more efficiently. Apple works hard to make the OS work as well as it looks, and Snow Leopard runs very well on the current hardware. I have no doubt that Apple will in the near future come out with something newer and better, but my guess is as good as anyone's as to what chip they will use.

General questions about JClient

1. We are having problems with a business application we have developed using BC4J and a JClient client. The performance is horrible. On one update form we have 7 comboboxes, two tabels, some labels and one textfield. It takes 12 - 15 seconds to load, first time, and 4 - 7 seconds second time. Isn't it possible to get better performance on complexe GUI's using JClient?
2. We have found out that the navigation binding on the comboboxes are about 10 - 15 times as slow as a LOV binding, but we are having problems using the LOV binding. The comboboxes work in a master - detail relationship, and we have that working with a view link and navigation binding. But we would like to use the faster LOV binding. Is it possible to use a LOV binding in a master - detail relationship?
3. Why are navigation bindings so slow compared to LOV bindings?
4. What are you general plans with JClient?
5. Could you possible refer to another project or currently running program that is build using JClient. We feel that we are a little alone on this issue. Is JClient only running on samples, or has it shown it's effeciency in real life.
6. It is running whitout problems in the samples and when we use the wizards to generate simple forms. But when we construct a complex GUI-structure we quickly run into performance problems. But also unexpected problems that we have difficulty solving, due to lack of documentation and knowledge.
We would really appreciate, if you would take the time to answer our questions.
A frustated development team.

1. We are having problems with a business application we have developed using BC4J and a JClient client. The performance is horrible. On one update form we have 7 comboboxes, two tabels, some labels and one textfield. It takes 12 - 15 seconds to load, first time, and 4 - 7 seconds second time. Isn't it possible to get better performance on complexe GUI's using JClient?Depends on how the application is setup. There are a number of options for deployment that affects how the client app will perform. Are you running JClient app in client-server mode?
Also in JDev 903, JClient designtime and runtime has fixed a number of issues that led to poor performance by default on a JClient wizard generated app by generating code that performs lazy load of controls and lazy bind of controls. This definitely affects the startup time of forms with tab windows such that only the required controls/bindings on the display is created to begin with.
Further more if you have a certain example situation that you want us to look at, we'd definitely give that a test to see where the performance bottle-necks are? From our work with other customers, we've seen examples where application assumptions have led to "performance degradation" and when you remove those assumptions, the performance improvements are "noticable" - like how many queries get executed when you startup? Are all those needed? Could the queries be optimized? How many controls come up? Are they all visible and bound? Could they be lazily rendered/bound? etc.
Yes, we do not have a suggested document yet, as JClient is still pretty new and customers are working on real-life apps which we've studied over time and are gathering "inputs" for best - practices kind of an article/example.
2. We have found out that the navigation binding on the comboboxes are about 10 - 15 times as slow as a LOV binding, but we are having problems using the LOV binding. The comboboxes work in a master - detail relationship, and we have that working with a view link and navigation binding. But we would like to use the faster LOV binding. Is it possible to use a LOV binding in a master - detail relationship? In JDev 902, LOV Binding was "fetching" all the data for LOV Bindings upfront, so if your data set is small it'd perform well, however in most realtime customer apps that we saw, we found this to be a problem as LOVs would take time to come up the first time. That's been fixed in 903. Now Lovs and Navigation bindings both respect the fetch sizes and other tuning parameters set on the Bc4J ViewObject. So you can tune the fetchsize/rangesize on the VO in the Bc4J object to control how much data is fetched upfront for a given binding. that will definitely affect performance and memory usage as based on a case by case basis, apps would determine what/how many rows should be fetched upfront vs. how many to fetch on scroll/navigation etc.
3. Why are navigation bindings so slow compared to LOV bindings?see 2 above.
4. What are you general plans with JClient?See the JClient docs on OTN (jdeveloper page) for general information.
If you have specific needs/questions we could sure get you answers for those.
5. Could you possible refer to another project or currently running program that is build using JClient. We feel that we are a little alone on this issue. Is JClient only running on samples, or has it shown it's effeciency in real life.Again JDeveloper home page has referenceslinks that indicate which customers have used what kind of applications. Note that JClient was released for the first time in JDev 9.0.2 so it's still going thru the first round of performance and usability improvements.
6. It is running whitout problems in the samples and when we use the wizards to generate simple forms. But when we construct a complex GUI-structure we quickly run into performance problems. But also unexpected problems that we have difficulty solving, due to lack of documentation and knowledge.This forum on OTN has a great amount of discussion on JClient issues and how to resolve various performance and other bugs in Jdev 902.
I agree on lack of complete documentation and examples and we're working towards that. Note that we did put up a Jclient Bindings demo which is a good example of how to "architect" a medium complexity application, how to layout controls, bind them, show/hide etc. An improved version of this example will be placed on OTN alongwith a version of JDev 903 when it is made available on OTN.
We would really appreciate, if you would take the time to answer our questions.
A frustated development team. And your critique/bugs/feature ideas are always welcome.

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