Excessive jshell imports

Importing all the class names when you are creating the jshell instance (~2600 classes) causes some severe lag when executing even simple REPL statements (eg. "int i = 0;")

The REPL isn't even responsive for almost a minute after starting up because its processing the evals for currentAddress, etc, which each take several seconds. The async nature of the console make it confusing because your input is accepted, but nothing happens.

Maybe just import a few hand-picked packages?