Stopped, Unable to validate WebLogic Domain

I got this error when I tried to start WebLogic through Eclipse:

Stopped, Unable to validate WebLogic Domain

Here is why:

when eclipse is working on java 6 (and it has to, because oracle development tools for helios requires java 6) and weblogic is running on java 5.

The workaround is simple:

add

-Dsun.lang.ClassLoader.allowArraySyntax=true

after -vmargs string in eclipse.ini