Here you can find the source of getAllInterfaces(Class clazz)
public static Class<?>[] getAllInterfaces(Class<?> clazz)
//package com.java2s; /*/*from w w w . j ava2 s.co m*/ * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ import java.util.*; public class Main { public static Class<?>[] getAllInterfaces(Class<?> clazz) { HashSet<Class<?>> interfaces = new HashSet<>(); getAllInterfaces(clazz, interfaces); return interfaces.toArray(new Class<?>[interfaces.size()]); } private static void getAllInterfaces(Class<?> clazz, HashSet<Class<?>> interfaces) { for (Class<?> iface : clazz.getInterfaces()) { if (!interfaces.contains(iface)) { interfaces.add(iface); getAllInterfaces(iface, interfaces); } } if (clazz.getSuperclass() != null) { getAllInterfaces(clazz.getSuperclass(), interfaces); } } }