Question: I want to sign a jar file that are containing another jar files and some class files.
Actually I know how to sign a jar file and I did it but here I have an applet file in which I used HttpClient of apache but when I run it from browser it gives an error org.apache.commons.httpclient methods are not found. So what should I do?
When I run this applet on applet viewer it runs but from browser it can't.
Please help me.

Answer: 
If you need to execute only signed code you should not include JAR files into your applet - instead you should include only the class files from the Jar-to-be-included into your applet.

If you sign the code afterwards also the class files from the jar are getting signed and therefore should be usable from within your applet.
I think the following steps should help:

* Sign all jar files you are using in your project
* Make sure all library jar files are included to the final app jar file

main jar manifest file should contain `Class-Path` key with relative path to jar files, included to the main jar file.
* When main application is built sign the main app jar file