Can I override and overload static methods in Java?

0 votes
asked Mar 19, 2010 by giri

I'd like to know:

  1. Why can't static methods be overridden in Java?
  2. Can static methods be overloaded in Java?

19 Answers

0 votes
answered Jan 19, 2010 by thilo

Static methods cannot be overridden because they are not dispatched on the object instance at runtime. The compiler decides which method gets called.

This is why you get a compiler warning when you write

 MyClass myObject = new MyClass();
 myObject.myStaticMethod();
 // should be written as
 MyClass.myStaticMethod()
 // because it is not dispatched on myObject
 myObject = new MySubClass();
 myObject.myStaticMethod(); 
 // still calls the static method in MyClass, NOT in MySubClass

Static methods can be overloaded (meaning that you can have the same method name for several methods as long as they have different parameter types).

 Integer.parseInt("10");
 Integer.parseInt("AA", 16);
0 votes
answered Mar 19, 2010 by volatiledream

Static methods can not be overridden because there is nothing to override, as they would be two different methods. For example

static class Class1 {
    public static int Method1(){
          return 0;
    }
}
static class Class2 extends Class1 {
    public static int Method1(){
          return 1;
    }

}
public static class Main {
    public static void main(String[] args){
          //Must explicitly chose Method1 from Class1 or Class2
          Class1.Method1();
          Class2.Method1();
    }
}

And yes static methods can be overloaded just like any other method.

0 votes
answered Jan 20, 2011 by manoranjan

Static methods can not be overridden because they are not part of the object's state. Rather, they belongs to the class (i.e they are class methods). It is ok to overload static (and final) methods.

0 votes
answered Mar 25, 2011 by opensas

Static methods can not be overridden in the exact sense of the word, but they can hide parent static methods

In practice it means that que compiler will decide which method to execute at compile time, and not in runtime, as it does with overridden instance methods.

For a neat example have a look here.

And this is java documentation explaining the difference between overriding instance methods and hiding class (static) methods.

Overriding: Overriding in Java simply means that the particular method would be called based on the run time type of the object and not on the compile time type of it (which is the case with overriden static methods)

Hiding: Parent class methods that are static are not part of a child class (although they are accessible), so there is no question of overriding it. Even if you add another static method in a subclass, identical to the one in its parent class, this subclass static method is unique and distinct from the static method in its parent class.

0 votes
answered Jan 14, 2012 by kumar-manish

Parent class methods that are static are not part of a child class (although they are accessible), so there is no question of overriding it. Even if you add another static method in a subclass, identical to the one in its parent class, this subclass static method is unique and distinct from the static method in its parent class.

0 votes
answered Jan 25, 2012 by dalee-bisen

If I m calling the method by using SubClass name MysubClass then subclass method display what it means static method can be overridden or not

class MyClass {
    static void myStaticMethod() {
        System.out.println("Im in sta1");
    }
}

class MySubClass extends MyClass {

    static void  myStaticMethod() {
        System.out.println("Im in sta123");
    }
}

public class My {
    public static void main(String arg[]) {

        MyClass myObject = new MyClass();
        myObject.myStaticMethod();
        // should be written as
        MyClass.myStaticMethod();
        // calling from subclass name
        MySubClass.myStaticMethod();
        myObject = new MySubClass();
        myObject.myStaticMethod(); 
        // still calls the static method in MyClass, NOT in MySubClass
    }
}
0 votes
answered Jan 13, 2013 by user2481001

No,Static methods can't be overriden as it is part of a class rather than an object. But one can overload static method.

0 votes
answered Jan 19, 2013 by charles-ma

You can overload a static method but you can't override a static method. Actually you can rewrite a static method in subclasses but this is not called a override because override should be related to polymorphism and dynamic binding. The static method belongs to the class so has nothing to do with those concepts. The rewrite of static method is more like a shadowing.

0 votes
answered Jan 21, 2013 by user2500552

No, you cannot override a static method. The static resolves against the class, not the instance.

public class Parent { 
    public static String getCName() { 
        return "I am the parent"; 
    } 
} 

public class Child extends Parent { 
    public static String getCName() { 
        return "I am the child"; 
    } 
} 

Each class has a static method getCName(). When you call on the Class name it behaves as you would expect and each returns the expected value.

@Test 
public void testGetCNameOnClass() { 
    assertThat(Parent.getCName(), is("I am the parent")); 
    assertThat(Child.getCName(), is("I am the child")); 
} 

No surprises in this unit test. But this is not overriding.This declaring something that has a name collision.

If we try to reach the static from an instance of the class (not a good practice), then it really shows:

private Parent cp = new Child(); 
`enter code here`
assertThat(cp.getCName(), is("I am the parent")); 

Even though cp is a Child, the static is resolved through the declared type, Parent, instead of the actual type of the object. For non-statics, this is resolved correctly because a non-static method can override a method of its parent.

0 votes
answered Jan 23, 2013 by narutouzumaki

static methods are class level methods.

Hiding concept is used for static methods.

See : http://www.coderanch.com/how-to/java/OverridingVsHiding

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