I'm installing Knowage in Windows. But when trying to make it work with OpenJDK 12, I've found several NoClassDefFoundError regarding classes in javax.xml (this one can be solved downloading small jar files) and sun.misc.BASE64Encoder (there are no jars for this one). Probably more, but those appear just trying to login. It seems to work fine with Java SE 8.
I have several solutions:
Leave Knowage with it's own Tomcat running Java SE 8, have a second Tomcat running Java 12 for any other app. But I'd like to avoid having two Tomcats, even if I'll have an Apache front-end proxying them anyway. Seems wasteful.
Fork Knowage, modify, compile, deploy, keep updated, redeploy, repeat. But I'd like to avoid the extra work.
Report an issue (done), wait for others to solve it. But I'd like to avoid the uncertainty of not knowing when it will be solved, if ever.
Take the rt.jar from Java SE 8, that has versions of those missing classes, place it in the tomcat/lib folder. I lean to this one, hence the title, at least until Knowage gets modified. But I don't know if this is safe. It seems to work: I can login! But, will it break the Universe or give headaches in the future?
Could you recommend me one solution or another?
I've recently been messing around with an open-source Java web app. I'm using JDK 7 locally but I know that the upstream builds using JDK 6.
I want to write some code that uses classes that only exist in JDK 7 (currently, ThreadLocalRandom). I can do that on my local system just fine, but when I want to send patches upstream I have to hunt down any such references and translate them to the equivalent JDK6-safe code, which is a pain in the butt.
Is there a way to have both JDK6 and JDK7 source in the project, and have Eclipse automatically use the appropriate version at compile time based on the project target? I would like something that's easy for both myself and the upstream maintainer, so nothing like weird build scripts or text replacement.
The project does use Guice, if that helps, although I think doing it at runtime might be too late (because then the maintainer wouldn't be able to compile using JDK6 tools).
I'm only at "dabbler" level in Java, so please use small words.
I want to integrate java compiler in my application but I don't have any idea how will I do that.
I want that user could compile and run code on my application.
If anyone can help me then please tell me from where I should start.
Starting Java 1.6, the standard JDK ships with an API to the compiler. Meaning, you can easily write a Java program that will compile other programs.
http://docs.oracle.com/javase/7/docs/api/javax/tools/JavaCompiler.html
EDIT as per Aaron's comment: an application using the compiler API must be run using the full JDK. The JRE doesn't include the compiler API implementation.
A second alternative is to embed the Eclipse Java compiler into your code. The advantage of this is that your application doesn't need a SDK to run - just add this single JAR.
Details are documented here: http://help.eclipse.org/kepler/index.jsp?topic=%2Forg.eclipse.jdt.doc.user%2Ftasks%2Ftask-using_batch_compiler.htm
Note: Adding a compiler to an application creates an enormous security risk. It basically means anyone can start doing anything with your application. Things that spring to mind are:
Attacking other computers, people and sites
Looking at all the data on the computer on which the application is running
Analyzing the network the computer is in and attacking any other computer in the same network
Installing Trojans or viruses on the computer
Our company is using eclipse since several years now (we are using WTP since release 0.7)
I am currently evaluating eclipse 3.6.2 with WTP 3.2.3 which should replace eclipse 3.4.2 with WTP 3.0.4 as being our main IDE.
And I have to say that once again I am quite disappointed in concerns of performance:
WTP 3.2.3 seems to be much slower than 3.0.4.
In fact I am really wondering why WTP gets slower with each release.
One of our applications (dynamic web project) contain about 4000 java classes and 700 jsps/jsp fragments. We only need basic WTP functionality for developing jsps, xmls and xsd. We don't need high sophistic features like Dali (should JPA tools really covered by a webtools project?), Libra or a visual xml editor in the first place.
Another interesting point is that WTP seems to slow down the whole IDE.
SWT is non-reponsive for some fraction of seconds, cpu usage is very high (especially after a built took place - if you look at the system jobs, several jsp/javascript indexers are doing work for some minutes, even if all WTP build validators have been disabled), opening new files are slower, navigating through the project etc.
This can be especially seen on older machines which do contains only a single core cpu.
The worst thing is that I've got the feeling that the WTP dev team does not care much about performance
(e.g. have a look at the http://wiki.eclipse.org/WTP_Performance_Tests page - last update took place in 2008).
Bug reports and Newsgroup posts regarding to performance of basic features (e.g. jsp editing/validating) are often ignored or closed after some time, some examples: here, here, and here.
Quo vadis, WTP?
Please don't get me wrong:
I don't want to blame WTP.
In fact I believe that WTP is a good open-source project developed by a talented team.
But obviously the project has a problem with its quality assurance, especially in terms of performance which affects usability and user acceptance.
I just want to point out that the team should focus on the things which are essential to most of the users in the first place and afterwards work on implementing super-duper-features.
My Questions
What are your experiences with WTP, especially the most recent releases?
Can you confirm or disprove my observations?
Are there better alternatives?
Did you switch from or to WTP and why?
Do you have some best practices to speed it up, especially for upper-mid-sized like ours?
UPDATE
I'd like to make an update on this question to reflect the current answers and
to sum up the current results:
Many users complain about more or less on the same issues so I see those issues as confirmed.
BTW, this question is also mentioned on a news post on theserverside.com with additional comments.
The responsible WTP project lead, nitind, made a notable post on the current situation of WTP, which I like to cite:
"The simple fact is that we don't spend much time on performance tests because we lack resources for doing that."
"Of course we'd like to be proactive about it rather than reactive, but we tend to allocate our time to functional problems first."
So this question turns a little bit into some kind of an open letter from the community to the WTP team:
Dear WTP team,
it's obvious that WTP is suffering from major quality/performance issues
which you try to play down or to ignore.
Please invest some time to improve the current situation
at the cost of new features and do everything what's required
to solve the current problems.
E.g. revive the performance team, do some regression tests between
previous releases or ask the community for (precise defined) help.
I am sure that they are enough people willing and able to help here.
If you like, do some kind of poll to get a feeling what should be
the most important scopes of future's WTP releases.
Please, please, listen to your community.
To respond, I'm the lead for the projects that supply the JSP, XML, and JavaScript source editing functionality in WTP. The simple fact is that we don't spend much time on performance tests because we lack resources for doing that. Of course we'd like to be proactive about it rather than reactive, but we tend to allocate our time to functional problems first. We do have an adopter product running performance regression tests regularly, but I expect that tests are run on multi-core machines by now--and we haven't had any new red flags reported to us for some time.
Of the 3 bugs you linked to, 2 predate the 3.0.4 version you laud and the third is either a formatting performance issue (since addressed) or one with as-you-type validation specific to XML files (the fixing of which would have triggered a memory leak in Xerces, iirc, hence us not putting it in at that time). If you have concrete projects that you can attach to a bug and say "doing X is slower in 3.2 by Y amount", we'll do what we can to figure out where there's a regression.
As for the indexers, they should at least eventually complete. The on-disk information that is stored has changed between WTP versions, and those files need to be reprocessed so they're again included in search and (where implemented) refactoring operations. Once the initial indexing is complete, it should act incrementally and be virtually unnoticeable. One architectural change you may be running into is that for JSPs, the entire workspace needs to be indexed in a single workbench session for that index to be considered "up to date". Shutting down Eclipse out of frustration will only prolong the impact of that reprocessing.
It sounds like your company's standard install includes the entirety of WTP rather than rolling your own custom distribution. I urge you to check the Startup and Shutdown preference page and turn off early startup of any functionality you're not interested in using. Nothing you've mentioned interest in makes use of that facility, but there are other areas of WTP and the Platform that do. Anything you're not interested in validating is fair game on the Validation preference page, as well as the setting to validate JSP fragments by default on the Web / JSP Files / Validation preference page.
We have the same problem with WTP 3.2.3 here, too. We use it in our product for several years, too but the acceptance of our developers and customers in this tool is decreasing every year because in every newer release it is slower and slower.
I would like to use it if I could disable all "advanced" features but as you mentioned you cannot disable the indexers at all. Also you cannot stop the validator of JSP files if it is already running (you can test this if you have that many files as you have and we also have around 1000 JSP files and many tag files in our project).
I also can prove that increasing the memory does not help. It only prevents crashes of the whole eclipse but it does not reduce the UI blocking internal operations of WTP.
In the newest version 3.2.3 I got many hangs when I start Tomcat from within the servers view. The UI just hangs about 1 minute. It's not only me who has the hangs, it's all my colleagues who work on Windows have the same problem. On Linux I do not know about this problem.
Also there are problems in WTP when you have no access to the internet. It seems there are request to some registries to download schemas or such things and if you do not have a connection then it just hangs and waits for the time out.
I don't know who's to blame: WTP or JBoss Tools.
The fact is that, as I work with GWT (minimal JSP), I went the opposite way: No WTP at all!!! I'm now using plain Eclipse for Java, and use a run configuration to deploy (programatically invoking ANT) and start the server, and I never looked back!!!
Eclipse used to take ~1.5GB and crashed several times. Now, it sits on ~800MB, and the whole environment became more stable.
I have seen similar effects, here's one solution that might be suitable in some project environments...
To guarantee fast and responsible Eclipse Web project environment, consider this:
Use Eclipse IDE for Java Developers
98MB version is leaner than 200MB EE version
from General / Startup and Shutdown, disable all but "Eclipse UI"
from Validation, disable validators which you do not need
these probably prevent some performance issues (YMMW)
Use Jetty
you do not need WTP or any other plugins, it's pure Java
like Tomcat but very quick & simple to install into any IDE / environment
embed directly into your project files, configure once for every developer
works in any IDE (Eclipse, IDEA, JDeveloper..)
start Servlet Container with "Debug As" / "Run As"
shutdown Servlet Container by clicking red box on Eclipse console
IDE Console, debugging & hot code replacement & JRebel works fine
Result: fast & responsive Eclipse when compared to many other Eclipse installations that use Eclipse EE version with WTP stuff.
Why? It might be that some Eclipse feature or plugin contains bugs or simply uses resources in a bad way and this makes Eclipse UI sluggish.
Non-Java EE Eclipse is good enough even for many Java EE project environments, it all depends on your architecture and what tools you are using..
Here's a quick tutorial to get started in case you wish to try Jetty Servlet Container out with Eclipse. See https://vaadin.com/web/jani/home/-/blogs/vaadin-for-everyone-how-to-get-started . Download VaadinProjectForAnyIDE.zip, it's an Eclipse project. Just ignore that Vaadin stuff and replace HelloWorldApplication.java with your own servlet and edit web.xml accordingly.
One more thing. With Eclipse EE version, you might also wish to try J2EE preview server which actually is Jetty embedded into Eclipse bundle. However, this also uses WTP mechanism.
I also think the stability and performance of Eclipse/WTP is somewhat alarming. I'm using Eclipse since mid 2003 and have been trying WTP since its very first releases.
At first the quality was absolute abysmal, but for a 0.x version I couldn't complain of course. While waiting for WTP to mature, I used MyEclipse, which was sort of okay but had its flaws too (and being partially based on WTP, inherited some of WTP).
When MyEclipse became heavier and heavier, slower and slower and we ran into several stability issues, we switched to 'pure WTP'. All we were using was really the basic JSP/JSF editor and deployer.
Since WTP doesn't do incremental deployment (at least not for the JBoss server runtime) we added the separate server runtime from JBoss tools. When we adopted Facelets, we also switched to the editor from JBoss tools.
We do however run into a lot of problems we also had with MyEclipse. There are unexplainable slowdowns, but much worse are various stability problems. There are lots of awkward exceptions and crashes. A typical .log file on many different workstations I examined is chockfull of exceptions. A small selection of the last 10 exceptions in my log:
1.
java.lang.NullPointerException
at org.eclipse.jst.jsp.core.internal.validation.JSPActionValidator.isElIgnored(JSPActionValidator.java:147)
2.
java.lang.RuntimeException
at org.eclipse.jface.viewers.ColumnViewer.checkBusy(ColumnViewer.java:763)
3.
java.lang.ArrayIndexOutOfBoundsException: 38
at org.eclipse.debug.internal.ui.viewers.model.FilterTransform$Node.addFilter(FilterTransform.java:67)
4.
org.eclipse.jdi.TimeoutException: Timeout occurred while waiting for packet 302111.
at org.eclipse.jdi.internal.connect.PacketReceiveManager.getReply(PacketReceiveManager.java:171)
5.
java.lang.NullPointerException
at org.eclipse.jst.jsf.facelet.core.internal.cm.ElementCMAdapter.getLength(ElementCMAdapter.java:109)
6.
Caused by: java.lang.NullPointerException
at org.eclipse.jst.jsf.facelet.core.internal.registry.taglib.WebappConfiguration.getConfigFilesFromContextParam(WebappConfiguration.java:184)
7.
org.eclipse.emf.ecore.resource.Resource$IOWrappedException: Feature 'span' not found. (file:///mysystem/Eclipse.app/Contents/MacOS/com
/sun/faces/metadata/taglib/facelets_jsf_core.taglib.xml, 453, 52)
at org.eclipse.emf.ecore.xmi.impl.XMLLoadImpl.handleErrors(XMLLoadImpl.java:83)
...
at org.eclipse.jst.jsf.facelet.core.internal.registry.taglib.TagModelLoader.loadFromInputStream(TagModelLoader.java:100)
8.
java.lang.NullPointerException: No IModelProvider exists for project P/my_project of version: Utility Module
at org.eclipse.jst.j2ee.model.ModelProviderManager.getModelProvider(ModelProviderManager.java:101
9.
java.lang.NullPointerException
at org.eclipse.jst.j2ee.internal.deployables.J2EEDeployableFactory.clearCache(J2EEDeployableFactory.java:238)
10.
org.eclipse.jst.jee.model.internal.mergers.ModelException: java.util.ConcurrentModificationException
at org.eclipse.jst.jee.model.internal.mergers.EjbJarMerger.process(EjbJarMerger.java:79)
Note that these are just the last 10, there are many, many more exceptions.
The casual reaction would be: "Your Eclipse install is corrupted! You have a local problem!" Yes, I might have a local problem, but this "local problem" seems widespread as many Eclipse installs I inspected seem to have this stuff in their logs.
I'm also having problems with deployments like reported at the following link in various incarnations: http://community.jboss.org/thread/158611 It may be JBoss tools specific or it may be based on the underlying WTP or even Eclipse code. I don't know, but I do know it's a nasty problem. Every WTP and JBoss tools version there is 'something' fixed, and every version a problem like that resurfaces in a slightly different form.
Between the stability problems I'm able to get some work done and I love the auto completion and navigate-into features the editors offer me (which keeps me from switching to a text editor and building completely on the command line), but I sure would love some increased stability.
By far the best way for speeding up my projects has been to precompile code that I am not currently using. We have about 20 projects that make up our system and when working on any specific problem I'm only touching a specific subset of those java files. Compiling most of the code that I won't be touching and throwing it into some .jar's, then using that as the source instead of including the projects has proven to speed up things by quite a bit. I imagine it will help you as well if you have 4k+ files.
Each project just has a little build.xml that will make a jar out of it to include.
As for the mind numbing slowness in the JSP editing. I have the same problems, it's just so dam slow. I don't have many more than 100 jsp files but I have the same issues as you. My solution has just been to throw money at hardware, which I must admit I enjoy doing :P.
To answer the following question:
Do you have some best practices to speed it up, especially for upper-mid-sized like ours?
Turning off validation and auto-building after file-saving is a good start to increase performance.
I've disabled the WTP JSP editor for the reasons you mentioned above: It just needs too many resources. Some more things you should consider:
Edit JSPs in the normal HTML editor. That means you don't get code completion which is a good thing. IMO, Mixing Java and HTML is a mistake in the first place and an editor can't fix that. Put all Java code into helper beans (which you can then test easily) and just access the beans from JSP. This should get rid of 99% of all the <% %> tags and solve most of your problems already.
Consider using Spring to be able to build more complex beans and inject them into your JSPs using these patterns:
How to inject spring beans into a jsp 2.0 SimpleTag?
Use SpringBeanAutowiringSupport:
<%!
#Autowired
private Bean bean;
public void jspInit() {
SpringBeanAutowiringSupport
.processInjectionBasedOnServletContext(
this, getServletContext()
);
}
%>
Try a different VM. WTP editors creates huge amounts of objects and now all VMs (GC implementations) can handle that equally well. If you use Sun's Java, try JRockit or IBMs J9. Also play with the GC settings. Increasing RAM won't help because if you have GC issues, more RAM usually only makes it worse (since the GC will have to process more data).
Precompile as much code as possible. You don't need 4000 classes open at all times on your workspace. Cut your huge project into manageable chunks.
Replace JSPs with plain Java servlets and use HTML rendering libraries like rendersnake or use a programming language which plays more nice with HTML (like Groovy).
Get some decent hardware. A new PC with a quad core and 8GB RAM costs $1000. If you save ten minutes every day, the investment will be paid up in 50 days (at the rate of 1 person costs $1000/day all in all).
Try MyEclipse which has much better web editors. The JSP editor is better than WTP (code completion works most of the time, for example) but it's still sluggish.
WTP (3.2.3) is slow for me too. I belive I have found some ways to make it not so slow:
We use maven, so there is a target directory which contains a copy of all JSP's and some other XML's. I have recognized that they are sometimes scanned by the WTP validators. But this is not necessary, so I have excluded them from validation (Project/Properties/Validation/XXX/Exclude Group/). (You should be able to gain the same effect when marking the target directory as derived, but that does not work for me some times ;-( )
I have made the (not scientifically proven) observation, that WTP seems to be faster with JSPX than JSP files.
If you need barebones Java EE then you are better off with Netbeans, if you need everything but just working you are better off with IDEA. It is as simple as that.
Couldn't comment so I will just put my comment in to this answer.
Have you tried upping Eclipse's memory allocation, I know it used to crash all the time when I used it on Mac OS X awhile ago. There is a config file that has the base RAM allocation in it, once I modified that file and gave it an extra 128 megabytes of memory it behaved better. Not sure if this will affect WTP, I am commenting more in regards to the core Eclipse application itself.
We have a web application that uses a third party java applet for encryption and authentication. It's always been a bit finicky, but right now it has me pulling my hair out.
Over the weekend, we migrated to a MS Load balanced cluster, upgraded our DNS, and rolled out all of the MS patches. Now the applet fails for all of our users who are using the MSJVM. The solution is simple, we just have them install a recent version of Sun, but I cannot figure out why the MSJVM is failing.
Every other configuration works (Firefox, Safari, IE with Sun on Window, Linux or Mac) or I can get to work with a reasonable amount of effort, but nothing I can do will make MSJVM work.
I understand the MSJVM is depreciated, but nothing on the site (http://www.microsoft.com/mscorp/java/default.mspx) indicates that it should no longer work. I am looking for information that will either allow us to make the MSJVM work so we can determine if it's easier to fix or install Sun, or that I can use to force our desktop configuration team to update the company policy on the MSJVM.
Thanks
Update 2009.10.19: It's clear that something disabled the MSJVM. We should reject users who are using that JVM but it hasn't been a priority to update the site. We've just been waiting them to fail and then directing them to install SUN.
Most likely the Java version used by your applet is superior than the one supported by the MSJVM.
I have followed your link but I could not find what that version was. I think is something previous to Java 1.2 ( like java 1.1.17 or soemthing like that )
If you happen to have an error message or a screenshot, troubleshooting would be easier.
But, yes, the definitive answer would be to use the latest version of the Java plugin.
I remember there were scripts ( javascript ) tha help to identify the Java version and provided a link to download the latest one, but I cannot find it now. Take a look at java.sun.com and see if you can find it.
Microsoft's JVM was never Java-compliant: http://en.wikipedia.org/wiki/Microsoft_Java_Virtual_Machine
The MSJVM never got beyond Java 1.1.x, which is very old. So any functionality which appeared with Java 1.2 (Java 2, as it was called), such as Swing, won't work. With the MSJVM, you're pretty much limited to AWT for the UI.
Licensing issues and lawsuits triggered by incompatibilities introduced by Microsoft (such as the delegate keyword) meant that Microsoft never took their JVM further.
As of July 30th 2009 I think it was after being extending numerous times the MS JVM is finally no longer supported and at end of life.
A workaround I have seen used before if you absolutely cannot rewrite it would be to use a custom VB script to launch the application, The script would do a quick change on the registry to make MSJVM the default when the app was launched then swap it back to whatever the setting was for normal operation.
i.e.
Set Registry for MS JVM as default
Launch Application
Reset Registry for Sun JRE 1.5.0_X as default.
I dont have the code handy, you should be able to find VB registry modification with a quick google. I can probably dig it up if your stuck.