I've frequently said that Java + JRebel gets the closest to the Common Lisp + slime experience (closer than Python) but as you say the Lisp experience is still superior, the Java ecosystem has yet to close the gap*. The widest part of that gap I'd mention is in not having the condition system built-in to Java (though I'm aware people have tried to make a comparable one as a library), lacking it degrades the debugging experience considerably (even though simple step-debugging is typically more pleasant than in Lisp). IntelliJ's drop frame feature isn't good enough. The other problem is needing Java + something. What you get with just a regular JVM running under your IDE is no better than what other languages offer (if they offer anything) as their cute hotswap/hotpatch feature and comes with big limitations. (Like no changing method signatures or no adding/removing methods or properties, or only applying changes to new objects.) Once you're doing something non-trivial, especially if you're trying to incrementally develop your program rather than just debug one specific problem, you'll have to restart. In contrast Common Lisp's got its disassemble, describe, inspect, compile, fmakunbound, ... all being functions callable at runtime, and update-instance-for-redefined-class is part of the standard language too. Support for live reloading of everything is baked into the language rather than a hack on top, slime is just a convenient way of working with it. It's still convenient to restart the program occasionally, but few things force you to.

Unfortunately JRebel has killed their free tier, so I'd now point unwilling-to-pay programmers to something like https://github.com/JetBrains/JetBrainsRuntime which is IntelliJ/Eclipse/whatever-independent. I haven't tried it myself yet though... Given they only address the biggest class reloading concerns, I doubt it's actually comparable to JRebel for business-world Java. JRebel handles among other things dynamic reloading from XML changes and reinitializing autowired Spring beans that other classes use for dependencies.

*Caveat, I've been out of the professional Java grind for a while, I'd be pleasantly surprised if some new version that's come out contradicts me.

I used this in the past: https://ssw.jku.at/dcevm/

Though nowadays the IntelliJ debugger with the OpenJDK is enough for me. I know what works and what doesn’t so I rarely feel frustrated.