This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
To create a jar file, use the jar tool that comes with the JDK. From the command line type: "jar" and it will show you the different commandline options. The most common command to create a JAR file looks like this: "jar cvf file.jar com\hp\blah\* " To un-jar a jar file, you can use a program like Winzip. For more info, check out this little guide: http://java.sun.com/products/jdk/1.1/docs/tooldocs/solaris/jar.html