Overriding static methods

[Douglas Cyporyn]

I believe my question hinges on the definition of "override".

I know the override rule about static methods to be as follows:

static methods cannot be overridden by non-static methods

non-static methods cannot be overridden by static methods

So, okay. We can override a static method with another static method. Great. But in doing so we lose the polymorphic behavior because the overriding static method only "hides" or "shadows" method in the super class.

Consider the following code:

class TestOvClass {

static public void write(){ System.out.println("ov class"); }

}

public class TestThisClass extends TestOvClass {

static public void write() { System.out.println("Test This Class"); }

public static void main(String[] args){

TestOvClass.write(); // prints ov class

TestThisClass.write(); // prints Test This Class

TestOvClass ov = new TestThisClass();
ov.write(); // prints ov class


}

}

We do not get the TestThisClass behavior in the ov.write() line. I understand this is because the ov reference variable is of type TestOvClass, and since the write method is static on that class, the JVM executes write as if it were TestOvClass.write() instead of running the method on the TestThisClass object the variable is referring to.

First, am I thinking of this in the right way?

Next, can we still say the method is overridden even if we do not get the polymorphic behavior? Is overriding merely a question for the compiler? If so then we can say yes, the compiler allows the override. Or is override a question for execution where we expect to benefit from polymorphism?

I can just imagine an exam question that would ask if the write method is overridden in TestThisClass. My response at this point is "yes, and no".

Thanks!
Doug

[Jelle Klap]

Referring to this as overriding is indeed not correct. The correct term would be hiding, as you said.
Your response should be a resounding "no".

[Roel De Nijs]

Overriding ONLY applies to instance methods, NOT to variables or static methods. But you can hide/shadow variables and/or static methods.

Douglas Cyporyn wrote:I can just imagine an exam question that would ask if the write method is overridden in TestThisClass. My response at this point is "yes, and no".

Just select the "No" radio button (because you learnt at CodeRanch that only instance methods can be overridden ) and you can confidently move on to the next question!