blob: a0b63618a007f634d535fb64599f812ac622ff53 (
plain) (
tree)
|
|
package cbt;
import java.io.*;
import java.lang.reflect.*;
import java.net.*;
import java.nio.*;
import java.nio.file.*;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
/**
* This launcher allows to start the JVM without loading anything else permanently into its
* classpath except for the launcher itself. That's why it is written in Java without
* dependencies outside the JDK.
*
* The main method loads the given class from the given class path, calls it's main
* methods passing in the additional arguments.
*/
public class NailgunLauncher{
/**
* Persistent cache for caching classloaders for the JVM life time. Can be used as needed by user
* code to improve startup time.
*/
public static ConcurrentHashMap classLoaderCacheKeys = new ConcurrentHashMap();
public static ConcurrentHashMap classLoaderCacheValues = new ConcurrentHashMap();
public static SecurityManager defaultSecurityManager = System.getSecurityManager();
public static void main(String[] args) throws ClassNotFoundException,
NoSuchMethodException,
IllegalAccessException,
InvocationTargetException,
MalformedURLException {
if (args.length < 3) {
System.out.println("usage: <main class> <class path> <... args>");
} else {
// TODO: cache this classloader, but invalidate on changes
String[] cp = args[1].split(File.pathSeparator);
URL[] urls = new URL[cp.length];
for(int i = 0; i < cp.length; i++){
urls[i] = new URL("file:"+cp[i]);
}
String[] newArgs = new String[args.length-2];
for(int i = 0; i < args.length-2; i++){
newArgs[i] = args[i+2];
}
new URLClassLoader( urls ){
public String toString(){
return super.toString() + "(\n " + Arrays.toString(urls) + "\n)";
}
}.loadClass(args[0])
.getMethod("main", String[].class)
.invoke( null/* _cls.newInstance()*/, (Object) newArgs );
}
}
}
|