Can we declare an abstract method final or static in java?

Java 8Object Oriented ProgrammingProgramming

A method which does not have body is known as abstract method. It contains only method signature with a semi colon and, an abstract keyword before it.

public abstract myMethod();

To use an abstract method, you need to inherit it by extending its class and provide implementation to it.

Declaring abstract method static

If you declare a method in a class abstract to use it, you must override this method in the subclass. But, overriding is not possible with static methods. Therefore, an abstract method cannot be static.

If you still, try to declare an abstract method static a compile time error is generated saying “illegal combination of modifiers − abstract and static”.

Example

In the following Java program, we are trying to declare an abstract method static.

 Live Demo

abstract class MyClass {
   public static abstract void display();
}
public class AbstractClassExample extends MyClass{
   public void display() {
      System.out.println("This is the subclass implementation of the display method ");
   }
   public static void main(String args[]) {
      new AbstractClassExample().display();
   }
}

Compile time error

On compiling, the above program generates the following error.

AbstractClassExample.java:2: error: illegal combination of modifiers: abstract and static
   public static abstract void display();
^
1 error

Declaring abstract method final

Similarly, you cannot override final methods in Java.
But, in-case of abstract, you must override an abstract method to use it.
Therefore, you cannot use abstract and final together before a method.

If, you still try to declare an abstract method final a compile time error is generated saying “illegal combination of modifiers: abstract and final”.

Example

In the following Java program, we are trying to declare an abstract method final.

public abstract class AbstractClassExample {
   public final abstract void display();
}

Compile time error

On compiling, the above program generates the following error.

AbstractClassExample.java:2: error: illegal combination of modifiers: abstract and final
public final abstract void display();
^
1 error
raja
Published on 03-Jul-2019 17:43:44
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