Question

I need to determine if a Class object representing an interface extends another interface, ie:

 package a.b.c.d;     public Interface IMyInterface extends a.b.d.c.ISomeOtherInterface{     } 

according to the spec Class.getSuperClass() will return null for an Interface.

If this Class represents either the Object class, an interface, a primitive type, or void, then null is returned.

Therefore the following won’t work.

Class interface = Class.ForName('a.b.c.d.IMyInterface') Class extendedInterface = interface.getSuperClass(); if(extendedInterface.getName().equals('a.b.d.c.ISomeOtherInterface')){     //do whatever here } 

any ideas?

Answer 1

Use Class.getInterfaces such as:

Class<?> c; // Your class for(Class<?> i : c.getInterfaces()) {      // test if i is your interface } 

Also the following code might be of help, it will give you a set with all super-classes and interfaces of a certain class:

public static Set<Class<?>> getInheritance(Class<?> in) {     LinkedHashSet<Class<?>> result = new LinkedHashSet<Class<?>>();      result.add(in);     getInheritance(in, result);      return result; }  /**  * Get inheritance of type.  *   * @param in  * @param result  */ private static void getInheritance(Class<?> in, Set<Class<?>> result) {     Class<?> superclass = getSuperclass(in);      if(superclass != null)     {         result.add(superclass);         getInheritance(superclass, result);     }      getInterfaceInheritance(in, result); }  /**  * Get interfaces that the type inherits from.  *   * @param in  * @param result  */ private static void getInterfaceInheritance(Class<?> in, Set<Class<?>> result) {     for(Class<?> c : in.getInterfaces())     {         result.add(c);          getInterfaceInheritance(c, result);     } }  /**  * Get superclass of class.  *   * @param in  * @return  */ private static Class<?> getSuperclass(Class<?> in) {     if(in == null)     {         return null;     }      if(in.isArray() && in != Object[].class)     {         Class<?> type = in.getComponentType();          while(type.isArray())         {             type = type.getComponentType();         }          return type;     }      return in.getSuperclass(); } 

Edit: Added some code to get all super-classes and interfaces of a certain class.