abstract
classes that can be converted to interfaces.
Using interfaces instead of classes is preferable as Java doesn't support multiple class inheritance, while a class can implement multiple interfaces.
A class may be converted to an interface if it has no superclasses (other
than Object), has only public static final
fields,
public abstract
methods, and public
inner classes.
Example:
abstract class Example {
public static final int MY_CONST = 42;
public abstract void foo();
}
class Inheritor extends Example {
@Override
public void foo() {
System.out.println(MY_CONST);
}
}
After the quick-fix is applied:
interface Example {
int MY_CONST = 42;
void foo();
}
class Inheritor implements Example {
@Override
public void foo() {
System.out.println(MY_CONST);
}
}
Configure the inspection:
Use the Report classes containing non-abstract methods when using Java 8 option to report only the classes with static
methods and non-abstract methods that can be converted to
default
methods (only applicable to language level of 8 or higher).