Detecting if a method is declared in an interface in Java

Question

Help me make this method more solid:

 /**
  * Check if the method is declared in the interface.
  * Assumes the method was obtained from a concrete class that 
  * implements the interface, and return true if the method overrides
  * a method from the interface.
  */
 public static boolean isDeclaredInInterface(Method method, Class<?> interfaceClass) {
     for (Method methodInInterface : interfaceClass.getMethods())
     {
         if (methodInInterface.getName().equals(method.getName()))
             return true;
     }
     return false;
 }

Answer 1

How about this:

try {
    interfaceClass.getMethod(method.getName(), method.getParameterTypes());
    return true;
} catch (NoSuchMethodException e) {
    return false;
}

Answer 2

This is a good start:

Replace:

for (Method methodInInterface : interfaceClass.getMethods())
 {
     if (methodInInterface.getName().equals(method.getName()))
         return true;
 }

with:

for (Method methodInInterface : interfaceClass.getMethods()) {
     if (methodInInterface.getName().equals(method.getName())) {
         return true;
     }
 }

:)

Answer 3

See Method#getDeclaringClass(), then just compare Class objects with the expected interface(s).

Answer 4

To make your method more robust, you probably also want to check if Class#isInterface() returns true for the given class and throw IllegalArgumentException otherwise.