When static method does not take part in overriding then why can we declare a throws clause.

[devasis majhi]

When static method does not take part in method overriding then why can't we declare a throws clause in a method of child class to throw a checked exception if the same is not declared in parent class.

Example:-

public class TestParent
{
   public static void name()
	{
		System.out.println("parent");
	}
}

public class Test extends TestParent
{
   public static void name() throws Exception
/*compilation error is thrown at this line.
 * Exception IOException is not compatible with throws clause
 */
	{
		System.out.println("child");
	}
}

[Campbell Ritchie]

Don’t know, but the Java Language Specification says a hiding method must not declare any new checked Exceptions. Just like an overriding method.

[Mike Simmons]

There's not really any good reason for this, in my opinion. The best reason I can think of is that it makes it easier if you need to refactor a static method to an instance method, or vice versa. Not a very strong reason, in my opinion, but it's something.

[Ivan Jozsef Balazs]

Another weak reason is the wish to support this transition:

void foo() {
  TestParent  t = null;
  t.name(); // does not throw a checked exception so we are okay
}

void foo() {
  Test t = null;
  t.name(); // but what about this? 
}

[Winston Gutkowski]

devasis majhi wrote:When static method does not take part in method overriding then why can't we declare a throws clause in a method of child class to throw a checked exception if the same is not declared in parent class.

Like the others, I don't really know. However, it's worth pointing out that method hiding is not generally a good idea anyway, so I can live with a few logical inconsistencies.

Winston

[Joe Areeda]

I don't really know either but it may have something to do with the throws and the way the compiler checks if you've caught or declared all user exceptions.

I haven't tried it but I wonder if it would let you do that if the base class could also throw the same exception?

Joe

[devasis majhi]

Same thing applicable to return type also. We cann't have any return type in static method of child class if parent class does not define the same.

public class TestParent {
	
	public static void name() 
	{
		System.out.println("par");
	}
}

public class Test extends TestParent{
	
	@Override
	public static int name() //Compilation error is thrown at this line.
                         // The return type is incompatible with TestParent.name()
	{
		System.out.println("chi");
                return 0;
	}
}

[Winston Gutkowski]

devasis majhi wrote:Same thing applicable to return type also. We cann't have any return type in static method of child class if parent class does not define the same...

OK, but I don't really understand why this is such a big deal for you.

The fact is that hiding methods is not a good thing, and the rules are what they are. Agonising about it seems like a poor use of your time.

Winston

[Edit] PS : Please DontWriteLongLines (←click). I've broken yours up this time.