The number of flaws that make Java inferior to other JVM languages is surprisingly small. By far the worst parts are excessively verbose "Beans", nullpointer by default, the JEE ecosystem (there are good alternatives) and the high RAM consumption (a JVM flaw). Honestly 80% of the value I derive from using a different JVM language come from avoiding NPEs, getters and setters. The remaining 20% can be very useful but they are certainly not essential nor can they be considered mandatory.