Re: Is clone a member function for array types?
On Dec 3, 12:06 pm, Daniel Pitts
<newsgroup.spamfil...@virtualinfinity.net> wrote:
t...@milkyway.gsfc.nasa.gov wrote:
According to the JLS clone is a public method for all array types:
6.4.5 Members of an Array Type
....
The public method clone, which overrides the method of the same name
in class Object and throws no checked exceptions. The return type of
the clone method of an array type T[] is T[].
....
However if I run the following program (JDK 1.5.0_04-b05 on Linux):
import java.lang.reflect.*;
public class Test {
public static void main(String[] args) {
int[] x = {1,2,3};
System.out.println("Class:"+x.getClass());
Class cls = x.getClass();
Method[] methods= cls.getMethods();
for(Method meth: methods) {
System.out.println("Method:"+meth);
}
}
}
I get the output
Class:class [I
Method:public native int java.lang.Object.hashCode()
Method:public final native java.lang.Class
java.lang.Object.getClass()
Method:public final native void java.lang.Object.wait(long) throws
java.lang.InterruptedException
Method:public final void java.lang.Object.wait(long,int) throws
java.lang.InterruptedException
Method:public fina lean java.lang.Object.equals(java.lang.Object)
Seem to have accidentally done some editing here.
This should be 'public boolean"...
Method:public final native void java.lang.Object.notify()
Method:public final native void java.lang.Object.notifyAll()
Method:public java.lang.String java.lang.Object.toString()
The clone method is missing.
The JavaDocs for the Class.getMethods is:
Returns an array containing Method objects reflecting all the public
member methods of the class or interface represented by this Class
object, including those declared by the class or interface and those
inherited from superclasses and superinterfaces.
So I should have gotten all the public methods, and clone is supposed
to be public, but it's
not showing up.... Does anyone have any idea what I'm missing?
Regards,
Tom McGlynn
hmm... Try using getDeclaredMembers to see. It could be that array
cloning is a special case, look at the VM spec to see if there are any
hints there. Array types *are* a special case in the JVM.
Do you mean getDeclaredMethods? I tried that but it returns an empty
array. That's OK in principle since the method might be declared in
some superclass of [I but getMethods should find it regardless of
where it's declared.
Although arrays are special, it seems very peculiar for there to be
objects of any type with methods not visible by reflection that may
still be invoked non-reflectively.
Regards,
Tom McGlynn