Java Invoke an embedded jar without dropping files to HDD

Code
package fuzzle;



import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.lang.reflect.Modifier;

import java.util.HashMap;

import java.util.Map;

import java.util.jar.JarEntry;

import java.util.jar.JarInputStream;



/**

 * Created by Pumpkins on 29/05/2015.

 *

 */

public class BCJInjector extends ClassLoader {

    private Map<String, byte[]> classes = new HashMap<String, byte[]>();

    public String mainClass;

    private Method m;



    public BCJInjector(String main, InputStream in) {

        super(BCJInjector.class.getClassLoader());

        try {

            JarInputStream jis = new JarInputStream(in);



            mainClass = main;//jis.getManifest().getMainAttributes().getValue("Main-Class");

            JarEntry je = null;

            String entryName = null;

            while ((je = jis.getNextJarEntry()) != null) {

                entryName = je.getName();

                if (je.getName().endsWith(".class")) {

                    String canonicalName = entryName.replaceAll("/", ".").replaceAll(".class", "");

                    try {

                        byte[] classBytes = readClass(jis);

                        classes.put(canonicalName, classBytes);

                        /*if (!canonicalName.equals(mainClass)) { //This gets done later to extract methods.

                            resolveClass(defineClass(canonicalName, classBytes, 0, classBytes.length));

                        }*/

                    } catch (Exception e) {

                        System.out.println("Failed to dynamically map a class.");

                    } finally {

                        //System.out.println("Resolved & defined: " + canonicalName);

                    }



                }

            }

            jis.close();

            in.close();



        } catch (IOException e) {

            e.printStackTrace();

        }



        Class<?> tClass = null;

        try {

            tClass = loadClass(mainClass);

            m = tClass.getMethod("main", new Class[] { new String[] {}.getClass() });

            m.setAccessible(true);

        } catch (ClassNotFoundException e) {

            e.printStackTrace();

        } catch (NoSuchMethodException e) {

            e.printStackTrace();

        }



    }



    public void startJar( String[] args ) throws ClassNotFoundException, IllegalAccessException, InstantiationException, NoSuchMethodException, InvocationTargetException {

        int mods = m.getModifiers();

        if (m.getReturnType() != void.class || !Modifier.isStatic(mods) || !Modifier.isPublic(mods)) {

            throw new NoSuchMethodException("main");

        }

        try {

            m.invoke(null, new Object[] { args });

        } catch (IllegalAccessException e) {

            e.printStackTrace();

        }

    }



    private byte[] readClass(InputStream stream) throws IOException {

        ByteArrayOutputStream baos = new ByteArrayOutputStream();

        while(true){

            int qwe = stream.read();

            if(qwe == -1) break;

            baos.write(qwe);

        }

        return baos.toByteArray();

    }



    public Class loadClass(String name) throws ClassNotFoundException {

        try {

            return this.getParent().loadClass(name);

        } catch (ClassNotFoundException e) {

            return findClass(name);

        }

    }



    public Class findClass(String name) throws ClassNotFoundException {

        byte[] classBytes = classes.get(name);

        return defineClass(name, classBytes, 0, classBytes.length);

    }



}