Make new jar from a existing jar

import java.io.BufferedInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Enumeration;
import java.util.jar.Attributes;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.JarOutputStream;
import java.util.jar.Manifest;

public class Test {

String destPath = "D:\\tmp\\b.jar";
String sourcePath = "D:\\tmp\\a.jar";

/**
* @param args
*/
public static void main(String[] args) {

Test test = new Test();
try {
test.run();
} catch (IOException e) {
e.printStackTrace();
}
}

public void run() throws IOException {
Manifest manifest = new Manifest();
manifest.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION,"1.0");
JarOutputStream target = new JarOutputStream(new FileOutputStream(destPath), manifest);
add(target);
target.close();
}

private void add(JarOutputStream target) throws IOException {
BufferedInputStream in = null;
try {
JarFile jarFile = new JarFile(sourcePath);

Enumeration<JarEntry> enu = jarFile.entries();

while (enu.hasMoreElements()) {
JarEntry oneEntry = enu.nextElement();
JarEntry entry = new JarEntry(oneEntry);
if (entry.getName().equalsIgnoreCase("META-INF/MANIFEST.MF")) {
continue;
}
target.putNextEntry(entry);
in = new BufferedInputStream(jarFile.getInputStream(oneEntry));

byte[] buffer = new byte[1024];
while (true) {
int count = in.read(buffer);
if (count == -1)
break;
target.write(buffer, 0, count);
}
target.closeEntry();
}

} finally {
if (in != null)
in.close();
}
}

}