Hello, I did : gkeytool then: errors: java.lang.NoClassDefFoundError: gnu/classpath/tools/keytool/Main <<No stacktrace available>> Caused by: java.lang.ClassNotFoundException: gnu.classpath.tools.keytool.Main not found in java.lang.ClassLoader $1{urls=[file:/usr/local/classpath/share/classpath/glibj.zip,file:/usr/local/classpath/bin/./,file:/usr/local/classpath/share/classpath/tools.zip], parent=null} at java.net.URLClassLoader.findClass(URLClassLoader.java:530) at java.lang.ClassLoader.loadClass(ClassLoader.java:342) at java.lang.ClassLoader$1.loadClass(ClassLoader.java:1112) at java.lang.ClassLoader.loadClass(ClassLoader.java:294) glibj.zip and tools.zip exist in /usr/local/classpath/share/classpath/ What should I do? Please help. thank you in advance haoyang