[jerven]

Q? did you ever try the jShell that comes with java11+. Curious what a REPL power user thinks about it.

[javajosh]

Haven't used it, but I can't imagine it would be great. Java's issue is that you can't do anything outside of a class. So there really is no outside context in which a REPL makes conceptual sense.

[jerven]

Well it is not that rigid. You can do code outside of a class/method

  jshell> var x=8
  x ==> 8

  jshell> x*3
  $2 ==> 24

etc.

But I haven't used it either as I never worked with a REPL other than SQL clients.

[register]

The REPL in CL allows you to redefine running code, even code compiled with high optimization levels. This is a feature of the language rather than a feature of the REPL but it's in the REPL that such features shine. In the best case in Java you can redefine methods when running under a debugger, using a framework such as JRebel or leveraging an application server/framework ( Play for example). When changes are too radical you have to recompile and redeploy. In CL this is only rarely needed. In short a REPL in Java will never be able to reach the level of interactivity provided by a CL REPL simply because interactive development is not built in the language as in the case of CL.