Native Methods.

[Purujit Saha]

public class TestClass
{
// insert declaration of a native method here
}

which of the following is correct,

1. native public void nativeMethod(int i);
2. private native void nativeMethod(int i);
3. protected int native nativeMethod();
4. public abstract native void nativeMethod(int i);
5. native int nativeMethod(int i) {}


Please give answer with explanation.
[ December 14, 2005: Message edited by: Purujit Saha ]

[ December 14, 2005: Message edited by: Purujit Saha ]
[ December 14, 2005: Message edited by: Purujit Saha ]

[Barry Gaunt]

The compiler will tell you the answer if the Java Language Specification does not.

[Gyan Shankar]

1. native public void nativeMethod(int i);
Ok
2. private native void nativeMethod(int i);
Ok
3. protected int native nativeMethod();
Not Ok. Should be protected native int nativeMethod();
4. public abstract native void nativeMethod(int i);
Not ok. Cannot be abstract and native at same time. Remove abstract.
5. native int nativeMethod(int i) {}
Not Ok. Cannot provide implementation here. It should come from native library.

[Leonardo Rafaeli]

so native void can have any modifier?

[Gyan Shankar]

As per 4 native method cannot be declared abstract

[Sasikanth Malladi]

Two simple rules:
native methods cannot be abstract.
native methods cannot have a body.
Other than that ntive methods follow the same rules as for regular methods.
Can you explain why the above two rules apply and are in place?
HTH,
Sashi
[ December 14, 2005: Message edited by: Sasikanth Malladi ]

[Gyan Shankar]

Native methods cannot be abstract because native means you will provide a implementation via some native language code but abstract means you wont so its contradictory.
Also native cannot have body because of the same explanation above.