eclipse magic: … Syntax error, varargs are only available if source level is 1.5 or greater

Question

Yesterday I made a project in eclipse, and it was working, compiling. I used Eclipse Galileo for Java EE. Today I open eclipse and see lots of errors saying that stuff is no

Answer 1

and something interesting for GWT. even though i am using java 6, it throw me error saying source level should be 5 or later.

Click the error, use the auto correct of eclipse, it change the compliance level to 5, solved the problem.