import java.lang.reflect.*;
import java.net.*;

public class Application implements Runnable {

protected URLClassLoader classLoader;
protected URL[] classPath;
protected String className;
protected Object[] args;
protected Exception applicationException;
protected boolean running;
 

public Application(String aClass, URL[] aClassPath) {
className = aClass;
classPath = classPath;
running = false;
classLoader = new URLClassLoader(
classPath,
Thread.currentThread() .getContextClassLoader());
args = new Object[1];
}

public Exception getApplicationException() {
return applicationException;
}

public void launch(String[] args) {
if (isRunning()) return;
this.args[0] = args;
applicationException = null;
Thread thread = new Thread( this,
"Running " +
className);
thread.setContextClassLoader(this.classLoader);
thread.start();
Thread.yield();
}

// Runnable targets
public void run() {

setRunning(true);
try {
this.resolveMain().invoke(null, args);
} catch (Exception ex) {
applicationException = ex;
} finally {
setRunning(false);
}
}

private Method resolveMain()
throws ClassNotFoundException,
NoSuchMethodException {
Class targetClass = this.classLoader.loadClass(className);
Class[] arg_types = { String[].class };
Method main = targetClass.getMethod("main", a rg_types);
int mask = Modifier.STATIC ^ Modifier.PUBLIC;
if ((main.getModifiers() & mask) != mask)
throw new NoSuchMethodException(
"Cannot find method public static void main(String[]) in class "+ className);
return main;
}

private synchronized void setRunning(boolean value) {
this.running = value;
notifyAll();
}

public synchronized boolean isRunning() { return run ning; }

public synchronized void waitFor() {
while (isRunning())
try {
wait();
} catch (InterruptedException ie) {}
}
}
 
 

Listing 2
package com.jpt.testcomp;

public class TestComponent {

public TestComponent() {}

public void runJava2Style(String implementation, String arg)
throws ClassNotFoundException,
InstantiationException,
IllegalAccessException {

Class clazz = Class.forName( implementation, true,
Thread.currentThread().getContextClassLoader());
TestComponentInterface tci = (TestComponentInterface)
clazz.newInstance();
tci.run(arg);
}

public void runJDK11Style(String implementation, String arg)
throws ClassNotFoundException,
InstantiationException,
IllegalAccessException {
Class clazz = Class.forName( implementation);
TestComponentInterface tci = (TestComponentInterface)
clazz.newInstance();
tci.run(arg);
}
}
 
 

Listing 3
public class MultiApplicationSecurityManager extends SecurityManager
throws SecurityException {

public void checkExit(int status) {

if ( Thread.currentThread().getContextClassLoader() !=
ClassLoader.getSystemClassLoader())
throw new SecurityException();

super.checkExit(status);

}
 
 

Listing 4
java.security.AccessControlException: access denied (java.lang.Runtime
Permission createClassLoader)
at java.security.AccessControlContext.checkPermission(AccessControlContext.
java:272)
at java.security.AccessController.checkPermission(AccessController.
java:399)
at java.lang.SecurityManager.checkPermission(SecurityManager.java:545)
at java.lang.SecurityManager.checkCreateClassLoader(SecurityManager.
java:610)
at java.lang.ClassLoader.<init>(ClassLoader.java:203)
at java.security.SecureClassLoader.<init>(SecureClassLoader.java:56)
at java.net.URLClassLoader.<init>(URLClassLoader.java:82)
at com.jpt.application.Application.<init>(./src/com/jpt/application
/Application.java:20)
at com.jpt.ui.JShell.launch(./src/com/jpt/ui/JShell.java:60)
at com.jpt.ui.JShell.main(./src/com/jpt/ui/JShell.java:72)
Exception in thread "main" Process terminated with exit code 1
 
 

Listing 5
/* AUTOMATICALLY GENERATED ON Sun Feb 03 15:43:44 EST 2002*/
/* DO NOT EDIT */

grant {
permission java.security.AllPermission;
};
 

Listing 6
Running JDK 1.1 Style on com.jpt.testapp.TestApplication1
Expected Exception:com.jpt.testapp.TestApplication1java.lang.ClassNotFoundException: com.jpt.testapp.TestApplication1
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:297)
at java.lang.ClassLoader.loadClass(ClassLoader.java:253)Running JDK 1.1 Style on com.jpt.testapp.TestApplication2
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:313)
at java.lang.Class.forName0(Native Method)
at java.lang.
Expected Exception:com.jpt.testapp.TestApplication2
Class.forName(Class.java:120)
at com.jpt.testcomp.TestComponent.runJDK11Style(Unknown Source)
at com.jpt.testapp.TestApplication1.start(Unknown Source)Running Java2 Style oncom.jpt.testapp.TestApplication1
at com.jpt.testapp.TestApplication1.main(Unknown Source)
at java.lang.reflect.Method.invoke(Native Method)
at com.jpt.mal
com.jpt.testapp.TestApplication1:0 sleeping
.component.Application.run(Unknown Source)
at java.lang.Thread.run(Thread.java:484)
java.lang.ClassNotFoundException:
com.jpt.testapp.TestApplication2Running JDK 1.1 Style on
com.jpt.testapp.TestApplication3
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
a
Expected Exception:com.jpt.testapp.TestApplication3
t java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:297)
at java.lang.ClassLoader.loadClass(ClassLoader.java:253)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:313)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:120)
at com.jpt.testcomp.TestComponent.runJDK11Style(Unknown Source)
at com.jpt.testapp.TestApplicaRunning
Java2 Style oncom.jpt.testapp.TestApplication2
com.jpt.testapp.TestApplication2:0 sleeping
tion2.start(Unknown Source)
at com.jpt.testapp.TestApplication2.main(Unknown Source)
at java.lang.reflect.Method.invoke(Native Method)
at com.jpt.mal.component.Application.run(Unknown Source)
at java.lang.Thread.run(Thread.java:484)
java.lang.ClassNotFoundException:
com.jpt.testapp.TestApplication3
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:297)
at java.lang.ClassLoader.loadClass(ClassLoader.java:253)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:313)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:120)
at com.jpt.testcomp.TestComponent.runJDK11Style(Unknown Source)
at com.jpt.testapp.TestApplicaRunning
Java2 Style oncom.jpt.testapp.TestApplication3
com.jpt.testapp.TestApplication3:0 sleeping
tion3.start(Unknown Source)
at com.jpt.testapp.TestApplication3.main(Unknown Source)
at java.lang.reflect.Method.invoke(Native Method)
at com.jpt.mal.component.Application.run(Unknown Source)
at java.lang.Thread.run(Thread.java:484)
com.jpt.testapp.TestApplication1:1 sleeping
com.jpt.testapp.TestApplication2:1 sleeping
com.jpt.testapp.TestApplication3:1 sleeping
com.jpt.testapp.TestApplication1:2 sleeping
com.jpt.testapp.TestApplication2:2 sleeping
com.jpt.testapp.TestApplication3:2 sleeping
com.jpt.testapp.TestApplication1 done!
com.jpt.testapp.TestApplication2 done!
com.jpt.testapp.TestApplication3 done!