Method used to extract classes.dex from an APK and copy it to a cache directory for processing.

gistfile1.java

private void extractDex(String apk) {
  	try {
	    JarFile file = new JarFile(apk);
	    Enumeration<JarEntry> entries = file.entries();
	    while (entries.hasMoreElements()) {
		    JarEntry entry = entries.nextElement();
		    if (entry.getName().equals("classes.dex")) {
			    File cache = getDir("dex_cache", Context.MODE_PRIVATE);
			    if (!cache.exists())
				    cache.mkdirs();
			    File classes = new File(cache + File.separator + "classes.dex");
			    InputStream stream = file.getInputStream(entry);
			    FileOutputStream fos = new FileOutputStream(classes);
			    while (stream.available() > 0)
				    fos.write(stream.read());
			    fos.close();
			    stream.close();
		    }
	    }
    } catch (IOException e) {
	    // TODO Auto-generated catch block
	    e.printStackTrace();
    }
}