- it is stable (both the language spec and the JVM) - new versions are backward-compatible - the language is simple therefore easy task are easy (junior devs can slowly get up to speed) - it still has a lot of momentum (momentum = a new corporate project is easy to start in Java) - there's been a lot of experience accumulated throughout the last two decades

All in all, it's good enough and it does not really have any glaring flaws.