Can you guess what happens?
I generated a client stub using Eclipse WTP [Axis2] and while working on a client I get Eclipse working very slowly when it tries to use Code Assist, that is, press a dot to get a list of methods, there's up to 30 seconds hang-ups of the workbench.
eclipse.buildId=M20090917-0800 java.version=1.6.0_15 java.vendor=Sun Microsystems Inc. BootLoader constants: OS=win32, ARCH=x86, WS=win32, NL=ru_RU Framework arguments: -product org.eclipse.epp.package.jee.product Command-line arguments: -os win32 -ws win32 -arch x86 -product org.eclipse.epp.package.jee.product
Warning Fri Jan 22 16:40:51 MSK 2010 The 'org.eclipse.mylyn.java.ui.javaAllCompletionProposalComputer' proposal computer from the 'org.eclipse.mylyn.java.ui' plug-in did not complete normally. The extension took too long to return from the 'computeCompletionProposals()' operation.
I was mucking with eclipse.ini and doubled the XXMaxPermSize to 512M. According to Sun:
MaxPermSize specifies the the maximum size for the permanent generation heap, a heap that holds objects such as classes and methods.
Like magic, the hang is gone. I would not be surprised if Eclipse uses the permanent generation heap to store/sort candidates for Content Assist and thrashes if the heap gets overloaded.
I had the same problem. Increased heap, changed VM, nothing worked. Until I found that one of my dependencies was a library shared via network drive. I copied the JAR locally and changed the dependency. My hang time went away.
I have the same problem. This is due to an error in workspace. My solution is get rid of error workspace, switch to another workspace folder and import my projects again.
Well for those interested: the only solution I found is get back to the Ganymede (The most recent version today is Galileo 3.5.1).
I tried Galileo Classic and Galileo 3.5.1 Java EE, both freshly downloaded, neither worked with that project. Eclipse hangs up and uses 100% of CPU resource.
Ganymede works fine.
If Mylyn is not used another solution could be to disable the automatic activation of the Mylyn plug-ins on startup: Window -> Preferences -> General -> Startup and Shutdown
This did it for me.
来源：https://stackoverflow.com/questions/2117880/eclipse-is-very-slow-when-using-code-assist-org-eclipse-mylyn-java-ui-javaallco