Here you can find the source of forName(String className, Class
@SuppressWarnings("unchecked") public static <T> Class<? extends T> forName(String className, Class<T> superType)
//package com.java2s; /**//from w w w. j a v a2 s .co m * Copyright 2016 Seznam.cz, a.s. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ public class Main { @SuppressWarnings("unchecked") public static <T> Class<? extends T> forName(String className, Class<T> superType) { try { Class<?> cls = Thread.currentThread().getContextClassLoader().loadClass(className); if (superType.isAssignableFrom(cls)) { return (Class<? extends T>) cls; } else { throw new IllegalStateException(className + " is not " + superType); } } catch (ClassNotFoundException e) { throw new IllegalStateException(e); } } }