I launched Eclipse earlier to jot down a snippet and was faced with the following as an error when I tried to run a fresh project:
An internal error occurred during: "Compute launch button tooltip".
That popup window shows as soon as I mouse-over the run icon in the top bar, or if I right click on the class in the explorer window and select any of the run/debug options.
After doing some research on the error, I see several people who posted similar messages but they all have been fresh installs of Eclipse. So note that this is not a fresh install, and that Eclipse was working fine earlier today. Also note that not only does my new project not run (with the normal main method), but projects I was running earlier have all stopped working with the same error.
Finally, also be aware that after seeing other people's suggestions on fixing this, one specifically said to select run configurations from the top of the page run menu. When I selected run configurations from this dropdown, I got the following message:
Exception occurred creating launch configuration tabs
Reason: Plug-in org.eclipse.jdt.debug.ui was unable to load class org.eclipse.jdt.internal.debug.ui.launcher.LocalJavaApplicationTabGroup
After that message, the run window opens but all of the tabs are missing. Like where you can set the display width and height, and the other tabs, they are all missing from the window now.
I was using Eclipse trouble free earlier today and I am sure no updates took place between when Eclipse was working and now. My question is of multiple parts: What is wrong in a nutshell? What could have caused this?
Got this from another site of some guy who got this same error after upgrading.
Worked for me as well.
Apparently putting the following line in your eclipse.ini helps:
-Dcom.ibm.icu.util.TimeZone.DefaultTimeZoneType=ICU
I never found out what went wrong, but a reinstall of eclipse fixed it. All projects survived seemingly undamaged. Thanks for the reply on the .ini but that did no good.
I had same error today - in an eclipse installation (Juno SR2 64bit) that has been running fine for months.
0: There were no changes on svn for my projects since yesterday (when it was running fine).
1: I restored the workspace from a 'Windows 7 -> Properties -> previous copy' backup. This failed because the directory structure of the '.metadata' contains folders with a deeper structure than is supported.
2: I restored the workspace from a overnight archive (gzipped so file depth is not an issue). This had no effect.
3: I tried to restore the eclipse installation directory (which seems to be updated an awful lot) from a 'Windows 7 -> Properties -> previous copy' backup. Again this failed - because of folder-depth issues (Note: it is installed in the root directory of my disk - so there is actually no way to use a restore on this installation!)
4: Had to delete the .metadata from my workspace and reinstall eclipse (and all the additional plugins), and re-import my projects, and setup all the servers, and android, etc, which took many hours.
The moral of the story? Backup both your workspace AND the eclipse installation every night manually. Windows Restore will NOT save you. Backing up your workspace is NOT enough.
Try setting the launch properties in:
Window>Preferences>Run/Debug(Expand)>Launching(Click)
Under launch Operations menu set it to:
Always launch the previously launched application
Click:
Apply>Ok
I had the same problem using eclipse mars. I cleared the folder .recommenders\index
And that solved my issue. Hope it helps.
incase you are having the eclipse files which you have downloaded from the official site .Just extract those file in the same folder where your previous eclipse was installed and select replace all. best solution
来源：https://stackoverflow.com/questions/12529629/eclipse-an-internal-error-occurred-during-compute-launch-button-tooltip