What is the difference between runnable jar library handling options?

So I will be using Java Web Start to deploy the java application. When exporting to a Runnable Jar, there are three options in eclipse Helios.

• Extract required libraries into JAR
• Package required libraries into JAR
• Copy required libraries into sub folder next to JAR.

What are differences, and how will they affect my .jnlp file?

If it's a single jar, isn't it easier because I wouldn't have to write all the different paths to all the libraries it uses?

If there are changes in both the library and the application, a single jar would be a better solution? Or would I need <jar href=''> for each individual libraries?

Also note that I need to make use of native libraries like .dll and .so files.