Whenever I read something like this I have a bad feeling about it. They are trying to get "C/C++" performance in Java by bypassing all the JVM's management and

Whenever I read something like this I have a bad feeling about it. They are trying to get "C/C++" performance in Java by bypassing all the JVM's management and garbage collection. They even basically reimplemented malloc() for memory heap management. Why not just ditch Java itself?