Join effort with HotswapHelper

[skybber]

I guess to join effort with HotswapHelper that:

• is based on HotswapAgent, that has parameter extraClasspath, that is used by classloaders to prioritize class loading from specified path. so it is possible to override classes in jars without jar recompilation
• makes life with HotswapAgent and dcevm much easier for end users

[Liubsyy]

It may be supported in JarEditor.
When using JarEditor to edit the class in the jar, it will first be saved to *jar_temp/jar_edit_out.
Maybe this can be used as extraClasspath.