Override/Change final class method implementing interface java

Question

Java - I have an Interface say InterfaceA that has three methods - method1, method2, method3.

A final class implements this interface. This class and interface are in a Jar and their implementations are unknown.

The Method method2 of class is not working as per expectations. What are possible ways in which i can have the right implementation/override this method.

Answer 1

In Java you cannot extend final classes.

---

So the only way is to code your own class with

• your own the method implementation
• call the final class methods in other cases

class Third implements TheInterfaceInQuestion {

    FinalClass fc;

    public Third() {
       fc = new FinalClass();
    }

    @Override
    public void method1() {
        // call final class implementation
        fc.method1();
    }

    @Override
    public void method2() {
        // new implementation
    }

    @Override
    public void method3() {
        // call final class implementation
        fc.method3();
    }

}