javamethodsstatic

Are values returned by static method are static?


Please consider this code

public class Utilities
{
     public static MyClass GetMyClass()
     {
          MyClass cls = new MyClass();
          return cls;
     }
}

Will this static method return a new instance of MyClass every time it is called? or it is going to return a reference to the same instance over and over?


Solution

  • Declaring a method static means it is a class method and can be called on the class without an instance (and can't access instance members because there's no object in context to use - no this).

    Look at the code below. Expected output:

    [1] Different
    [2] Same
    

    If you want a variable to have the lifetime of the class and return the same object every time also declare the variable as static in the class:

    public static String getThing(){
        String r=new String("ABC");//Created every time the method is invoked.
        return r;
    }
    
    private static String sr=new String("ABC");//Static member - one for the whole class.
    
    public static String getStaticThing(){
        return sr;
    }
    
    public static void main (String[] args) throws java.lang.Exception
    {
        String thing1=getThing();
        String thing2=getThing();
        if(thing1==thing2){
            System.out.println("[1] Same");
        }else{
            System.out.println("[1] Different");
        }
        
        String thing1s=getStaticThing();
        String thing2s=getStaticThing();
        if(thing1s==thing2s){
            System.out.println("[2] Same");
        }else{
            System.out.println("[2] Different");
        }
    }