Everytimes, I change the java coding in java class under Eclipse. I click the run-as, it requires to restart the embedded Tomcat server in order to make the change effective. How can I test the change without the need to restart the Tomcat server. Because it is very time-consuming, if I need to restart the embedded Tomcat server whenever I change some coding. It will spend one minute for testing a little change.
Thanks
What you need is a hot deploy:
Hot-deployable services are those which can be added to or removed
from the running server. It is the ability to change ON-THE-FLY what’s
currently deployed without redeploying it.
Hot deployment is VERY hot for development. The time savings realized
when your developers can simply run their build and have the new code
auto-deploy instead of build, shutdown, startup is massive.
And good news there is a hot deploy in Eclipse. Just Follow the Eclipse tutorial for this
This process is called hot swap or also hot deploy. There are tools that do this process for you. One open source tool that you can check is HotSwapAgent. One paid alternative would be JRebel.
Obviously goes without saying that these two are far from comparable in terms of features and efficiency. But if it is just for testing purposes the open source alternative is just fine. In industry, not that much(we have tried it in my company and didn't fit our expectations).
If i am not wrong there is a option to do that. I am pretty sure that you have seen that.
Is there any way to get the java code changed without hybris server restart. Its taking long time for each java code change and then server restart. Development time get increase and productivity decrease. One way is JRebel but that is license tool and evaluation version last till 15 days only. I am looking for any opensource tool or specific configuration to reflect java code changes without server restart.
I am using hybris 5.4.
As we know hybris server is hybris modified tomcat server.
For hybris issues you can better ask the hybris-support.
Besides of that, as I developed in hybris I used JRebel, which worked very good. I dont know other helpful things for that. And yes, its annoying to restart the hybris at every codechange... but JRebel is a good solution.
I am currently using DCEVM (Dynamic Code Evolution VM) https://dcevm.github.io/
It does not offer all the features that JREBEL does but for me is extremely helpfull.
Please note that, from my knowledge, it is not compatible with JREBEL.
We used "HotSwap" which was a functionality of Eclipse. I believe Intellij has similar support. This lets you change class methods in real time.
The downside is this only works in the body of methods. You CANNOT alter a method's signature (ie Number of args, name, return type, etc) or create new classes.
But still better than nothing!
You can try out jrebel, we have been successfully using jrebel for hot swap in Hybris, they also provide all the set up steps necessary for integrating jrebel to you environment.
I've got a huge web project in eclipse using maven. After each change in any of Java classes in my daos or services or controllers when I restart tomcat the change doesn't get picked up. So I need to do maven update--restart tomcat or clean--maven install--restart tomcat to get the change picked on the next server restart. So, in other words, tomcat doesn't pick any changes on a restart. I know there might be 100 reasons for this but could anyone please share some likely causes since the productivity is quite low if I have to make maven install each time for a change to be picked? thank you
Well, mvn clean install and then tomcat restart is quite common pattern for application deployment. In theory you can speed it up a little bit with things like JRebel.
In practice most people are quite happy with some build configuration inside their favourite IDE, which will make all these build/deploy things with one button click.
Reading through Eclipse debug topics I did not find an answer to my specific problem. I wonder if anybody else has seen it. I only experience this since switching to Luna, I used Kepler and Indigo before.
I usually debug Tomcat, but it happens for any one-class test app. When the app hits the first breakpoint, Debug view is shown, then I have to wait 20-30 seconds for the debugger to initialize, and only then is the code line highlighted in the editor. From that point on every break is immediate. Other kind of slowness is not experienced. In Tomcat any subsequent request stops quickly. The problem is that it's restarted often when hot code replacement is not feasible.
Anybody knows how to tweak it? There is no building or validating process going on at that time, and I tried to allocate various amounts of memory to Eclipse. -Xms256m, -Xmx2048m usually works very well for me.
Clearing all breakpoints worked for me too. Probably it was because of that breakpoint in jar files it would be taking more time for generating line numbers for those files.
I don't know how to tweak it, but in experiencing the same problem I found an Eclipse bug ticket already created for this along with duplicates: 440470 (https://bugs.eclipse.org/bugs/show_bug.cgi?id=440470).
Starting Eclipse with "-consolelog -debug" hasn't showed any additional errors related to this.
I am working with a large core Java project and have also installed EMF (Eclipse Modeling Framework) and GEF (Graphical Editor Framework) plugin packages and dependencies via update site. I have installed these in previous versions of Eclipse without the debug delay issue. I tried closing this project and created a new test project with a simple Java class. There was no delay when debugging this class.
I found this post trying solve my issue: Very very slow to initialize tomcat, hibernate, etc. If you fall down here for similar problem I would suggest you what resolved to me. Try:
Clear all breakpoints, mainly those in API's, clear expressions too.
That's what worked for me.
My issue was fixed in Luna SR1.
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.