Java Reflection Method Main Invoke invokeMain(String className, String[] args, ClassLoader classLoader)

Description

Invokes the application in this jar file given the name of the main class and an array of arguments.

License

Apache License

Parameter

Parameter	Description
className	the name of the main class
args	the arguments for the application

Declaration

public static void invokeMain(String className, String[] args, ClassLoader classLoader)
        throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException 

Method Source Code

//package com.java2s;
/*//from w ww. j a  v  a  2  s  .  co  m
 * Copyright 2013 Decebal Suiu
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this work except in compliance with
 * the License. You may obtain a copy of the License in the LICENSE file, or 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.
 */

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

public class Main {
    /**
     * Invokes the application in this jar file given the name of the main class
     * and an array of arguments. The class must define a static method "main"
     * which takes an array of String arguemtns and is of return type "void".
     *
     * @param className
     *                   the name of the main class
     * @param args
     *                   the arguments for the application
     * @exception ClassNotFoundException
     *                        if the specified class could not be found
     * @exception NoSuchMethodException
     *                        if the specified class does not contain a "main" method
     * @exception InvocationTargetException
     *                        if the application raised an exception
     */
    public static void invokeMain(String className, String[] args, ClassLoader classLoader)
            throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException {
        Class<?> clazz = classLoader.loadClass(className);
        Method method = clazz.getMethod("main", new Class[] { args.getClass() });
        method.setAccessible(true);
        int mods = method.getModifiers();
        if (method.getReturnType() != void.class || !Modifier.isStatic(mods) || !Modifier.isPublic(mods)) {
            throw new NoSuchMethodException("main");
        }
        try {
            method.invoke(null, new Object[] { args });
        } catch (IllegalAccessException e) {
            // this should not happen, as we have disabled access checks
        }
    }
}

Related

1. invokeMain(Class clazz, String[] args)
2. invokeMain(Class fooClass)
3. invokeMain(Class mainClass, List args)
4. invokeMain(ClassLoader classloader, String classname, String[] args)
5. invokeMain(Method main, String[] args)
6. invokeMain(String... args)