Hot code replacement (HCR), which doesn’t require a restart, is a fast debugging technique in which the Java debugger transmits new class files over the debugging channel to another JVM.
https://blogs.msdn.microsoft.com/visualstudio/2018/02/02/hot-code-replacement-for-java-comes-to-visual-studio-code/
https://blogs.msdn.microsoft.com/visualstudio/2018/02/02/hot-code-replacement-for-java-comes-to-visual-studio-code/