A BASIC compiler:
You write sourcecode similar to VB6 and with Jabaco you can compile it to bytecode which is similar to the output of the Java programing language.
An integrated development environment (IDE):
Autocompletion, code highlighting, object browsing, a GUI editor and other modern IDE-stuff will support you in your tasks.
Start the project, step through your sourcelines, readout your vars, fix some bugs and continue the session without a restart.
An idea to do something different:
Jabaco must be much more than that to exist. It needs a lively framework and an active community - it is on you to decide.