Compress String

Code
import java.io.ByteArrayOutputStream;
java.io.IOException;
import java.util.zip.GZIPOutputStream;
import java.util.zip.*;
 
public class zipUtil{
public static String compress(String str){
    if (str == null || str.length() == 0) {
        return str;
    }
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    GZIPOutputStream gzip = new GZIPOutputStream(out);
    gzip.write(str.getBytes());
    gzip.close();
    return out.toString("ISO-8859-1");
 }
 
 public static void main(String[] args) throws IOException {
String string = "admin";
    System.out.println("after compress:");
    System.out.println(ZipUtil.compress(string));
 
  }
}