Keywords
JRebel is a massively time-saving Java Virtual Machine (JVM) hot reloader, especially useful for development of larger Jakarta EE applications where the full redeployment development cycle can be prohibitive.
It's a no brainer. If you are developing with Java™ or Jakarta EE – or anything that is JVM-based (Scala, Groovy) get JRebel! It can't quick cover every hot reload case, and is perhaps not as immediate as development with or JavaScript, but if you are working with Java, JRebel will get you pretty close to the convenience of other languages. It costs $$$ but will also help save you time=money and your sanity.
It also plays particularly nicely with Jakarta Faces – formerly JavaServer Faces (JSF).
And it has plugins for popular IDEs such as JetBrains IntelliJ IDEA and NetBeans.
And there is also XRebel for profiling and performance analysis.