Compiler Error J0168

The declaration of an abstract method must appear within an abstract class

The compiler detected a method declared with the modifier abstract within a class which was not defined as abstract. This error usually occurs when a class is intended to be abstract but is missing the abstract modifier in the class declaration. Either change the class so it is declared as abstract or remove the modifier from the methods defined in the class.

The following example illustrates this error:

public class Simple {
   
   abstract void method1();
      // error: class must also be abstract
}