NULL cannot be resolved

From JavaErrors

If you get the error

 NULL cannot be resolved

then you probably have a simple typo.

The null value is all lowercase in Java: "null" and not "NULL".

WRONG

 if(foo == NULL)   // uppercase is used in other languages but not Java
 {
   // stuff
 }

CORRECT

 if(foo == null)   // better!
 {
   // stuff
 }