There was a java.lang.OutOfMemoryError: Java heap space error when running myeclipse today. The solution is as follows:
Modify from IntalledJREs; window->Preferences->Java->InstalledJREs, select the current JRE, and then edit it; in the new window, set Default VM Arguments to -Xms512M -Xmx512M; this setting should be valid for all projects .
It is also possible to modify it to -Xms64m -Xmx256m.