Java's garbage collection is far from the state of the art in GC technology. While there are some non-standard JVMs that have advanced GC (such as IBM's real-time garbage collector), the standard JVM does not.
Current-generation garbage collectors have far better performance, and many research GCs support concurrent, pause-free collection.
(And that leaves aside the non-performance benefits of a GC, in terms of engineering simplicity and bug elimination.)
Does require custom hardware or kernel cooperation for speed (e.g. it needs to do batched MMU operations without clearing the TBL on each 2MB page). Looks like it's got a better read barrier than the Pauseless one; that does of course cost extra on stock hardware.
Current-generation garbage collectors have far better performance, and many research GCs support concurrent, pause-free collection.
(And that leaves aside the non-performance benefits of a GC, in terms of engineering simplicity and bug elimination.)