Compiler Error J0254

Cannot change predefined symbol

The compiler detected an attempt to use the #define or #undef directive on a symbol already defined in Java. This error occurs when a symbol such as true or false, which are already defined for conditional compilation, is redefined using the #define or #undef conditional compilation directives. Remove or change the #define or #undef directives specified in the error and compile again.

The following example illustrates this error:

#undef false //error: cannot undefine the 'false' symbol
#define true //error: cannot define the predefined 'true' symbol

public class Simple{
   //do something here
}