File targetFile = new File(targetDir, fileName.replace('/', File.separatorChar) + ".class");
jarName = jarName+".class";
if (targetFile.exists())
{
String sourceClassName = name.replace('/', '.');
String targetClassName = remapper.map(name).replace('/', '.');
JarEntry entry = sourceZip.getJarEntry(jarName);
byte[] vanillaBytes = entry != null ? ByteStreams.toByteArray(sourceZip.getInputStream(entry)) : new byte[0];
byte[] patchedBytes = Files.toByteArray(targetFile);