Pablo Fernandez Pablo Fernandez - 3 months ago 8
Java Question

How to determine by reflection if a Method returns 'void'

I have a

java.lang.reflect.Method
object and I would like to know if it's return type is
void
.

I've checked the Javadocs and there is a
getReturnType()
method that returns a Class object. The thing is that they don't say what would be the return type if the method is void.

Thanks!

Answer
if( method.getReturnType().equals(Void.TYPE)){
    out.println("It does");
 }

Quick sample:

$cat X.java  

import java.lang.reflect.Method;


public class X {
    public static void main( String [] args ) {
        for( Method m : X.class.getMethods() ) {
            if( m.getReturnType().equals(Void.TYPE)){
                System.out.println( m.getName()  + " returns void ");
            }
        }
    }

    public void hello(){}
}
$java X
hello returns void 
main returns void 
wait returns void 
wait returns void 
wait returns void 
notify returns void 
notifyAll returns void
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