The 'Cannot find symbol' error in Java occurs due to typos and missing import statements. Follow these suggestions to fix it successfully.

Strangely, the unresolved symbols can be found and used in my scala code. It seems that only java code can not resolve these classes.

I just added a FileDialog method to my java app (Cocoa-Java, but I think this is java related) and am getting this error:threads/frog.java:33: cannot resolve symbol ...