What does the Java Applet security warning “JAR file manifest does not contain the Permissions attribute”mean?

Question

I have a Java Applet which needs access to the local filesystem of the client. I have created a simple certificate for my own (it is NOT certified by Verisign,Commodo, ...). I s

Answer 1

I ran into the same problem and changing my manifest did not fix it.

Finally I found out, that I referenced a library which came in its own jar with its own manifest. I was using a copy of that jar-file that did not have Permissions and Codebase.

So, if you reference any libraries except the JRE System library, check the manifest in the jar file (e.g. by opening it with 7zip). If it does not contain the attributes, you can:

• check, if the manufacturer has a new version. He might have noticed the problem by now.
• Unzip the jar file, edit the manifest and jar it again, or
• Merge the library with your own jar.

For the last two, check the license under which the library is published. Maybe you are not allowed to manipulate the product this way.