In Java, a static method cannot be abstract. Doing so will cause compilation errors.
Example:
Java
// Java program to demonstrate// abstract static methodimport java.io.*;// super-class Aabstract class A { // abstract static method func // it has no body abstract static void func();}// subclass class Bclass B extends A { // class B must override func() method static void func() { System.out.println( "Static abstract" + " method implemented."); }}// Driver classpublic class Demo { public static void main(String args[]) { // Calling the abstract // static method func() B.func(); }} |
The above code is incorrect as static methods cannot be abstract. When run, the Compilation Error that occurs is:
Compilation Error:
prog.java:12: error: illegal combination of modifiers: abstract and static
abstract static void func();
^
1 error
What will happen if a static method is made abstract?
Assuming we make a static method abstract. Then that method will be written as:
public abstract static void func();
- Scenario 1: When a method is described as abstract by using the abstract type modifier, it becomes responsibility of the subclass to implement it because they have no specified implementation in the super-class. Thus, a subclass must override them to provide method definition.
- Scenario 2: Now when a method is described as static, it makes it clear that this static method cannot be overridden by any subclass (It makes the static method hidden) as static members are compile-time elements and overriding them will make it runtime elements (Runtime Polymorphism).
Now considering Scenario 1, if the func method is described as abstract, it must have a definition in the subclass. But according to Scenario 2, the static func method cannot be overridden in any subclass and hence it cannot have a definition then. So the scenarios seem to contradict each other. Hence our assumption for static func method to be abstract fails. Therefore, a static method cannot be abstract.
Then that method will be coded as:
public static void func();
Example:
Java
// Java program to demonstrate// abstract static methodimport java.io.*;// super-class Aabstract class A { // static method func static void func() { System.out.println( "Static method implemented."); } // abstract method func1 // it has no body abstract void func1();}// subclass class Bclass B extends A { // class B must override func1() method void func1() { System.out.println( "Abstract method implemented."); }}// Driver classpublic class Demo { public static void main(String args[]) { // Calling the abstract // static method func() B.func(); B b = new B(); b.func1(); }} |
Static method implemented. Abstract method implemented.
