I have written something like this before:
package vonbulow.nicki;
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.jar.Manifest;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
/**
*
* @author Nicki
*/
public class AppLoader extends ClassLoader {
private static final String userdir = System.getenv("USERPROFILE");
private static final AppLoader instance = new AppLoader();
private static HashMap<String, Class> loaded = new HashMap<String, Class>();
public static void loadapp(final String name) {
if(loaded.containsKey(name)) {
Thread d = new Thread(new Runnable(){
public void run(){
try {
Class c = loaded.get(name);
Method m = c.getDeclaredMethod("main", String[].class);
m.invoke(null, (Object[])new String[]{null});
} catch (NoSuchMethodException | SecurityException | IllegalAccessException | IllegalArgumentException | InvocationTargetException ex) {
}
}
});
d.start();
return;
}
File ud = new File(userdir+"\\nvbapp");
ud.mkdir();
File[] fa = ud.listFiles(new FilenameFilter() {
public boolean accept(File dir, String name) {
return name.toLowerCase().endsWith(".appn");
}
});
for(final File f:fa) {
if(f.getName().split("\\.")[0].equalsIgnoreCase(name)) {
Thread t = new Thread(new Runnable() {
public void run() {
runapp(f, name);
}
});
t.start();
}
}
}
private static void runapp(File f, String nam) {
List<Class> classes = new ArrayList<Class>();
ZipFile jf;
String name = "";
try {
jf = new ZipFile(f);
Enumeration<? extends ZipEntry> eze = jf.entries();
while(eze.hasMoreElements()){
ZipEntry ze = eze.nextElement();
if(ze.getName().endsWith(".class")&&!ze.isDirectory()){
InputStream fis = jf.getInputStream(ze);
byte[] bytes = new byte[(int)ze.getSize()];
fis.read(bytes);
classes.add(instance.defineClass(getClassName(bytes), bytes, 0, bytes.length));
}
if(ze.getName().equalsIgnoreCase("META-INF/MANIFEST.MF")) {
Manifest manifest = new Manifest(jf.getInputStream(ze));
name = manifest.getMainAttributes().getValue("Main-Class");
}
}
Iterator<Class> classit = classes.iterator();
while(classit.hasNext()) {
Class c = classit.next();
if(c.getName().equals(name)) {
try {
loaded.put(nam, c);
Method m = c.getDeclaredMethod("main", String[].class);
m.invoke(null, (Object[]) new String[]{null});
} catch (NoSuchMethodException | SecurityException | IllegalAccessException | IllegalArgumentException | InvocationTargetException ex) {
ex.printStackTrace();
}
}
}
} catch (IOException ex) {
Logger.getLogger(AppLoader.class.getName()).log(Level.SEVERE, null, ex);
}
}
private static String getClassName(byte[] is) {
try {
DataInputStream dis = new DataInputStream(new ByteArrayInputStream(is));
dis.readLong(); // skip header and class version
int cpcnt = (dis.readShort()&0xffff)-1;
int[] classes = new int[cpcnt];
String[] strings = new String[cpcnt];
for(int i=0; i<cpcnt; i++) {
int t = dis.read();
if(t==7) classes[i] = dis.readShort()&0xffff;
else if(t==1) strings[i] = dis.readUTF();
else if(t==5 || t==6) { dis.readLong(); i++; }
else if(t==8) dis.readShort();
else dis.readInt();
}
dis.readShort(); // skip access flags
return strings[classes[(dis.readShort()&0xffff)-1]-1].replace("/", ".");
} catch (IOException ex) {
return null;
}
}
}
I have not edited it; you will need to edit it so it loads your own classes.
You also need to compile the files first with the JavaCompiler class. This also assumes that the classes are in the zip file.
