In a sense, both :). Java made GC mainstream and since Hotspot has an excellent GC, solving the problem for many use cases. However, the Java language design is extremely performance-hostile with respect to memory allocations. Notable points are:

- no value types mean, that there are tons of separate heap allocations which have to be referenced by pointers, this puts a ton of unnecessary load on the GC. It also means, that you fully depend on escape analysis when passing objects to functions for avoiding heap allocation. And the existing primitive types (int, float) often require boxing.

- the design of the standard libraries was, especially at the beginning full of wasteful allocations. Most string handling code was a constant series of allocations (having 16 byte chars didn't help this either).

- far to many Java libraries build extremely complex object hierarchies and protocols. Just reading from a text file means instantiating several objects. This adds to the GC pressure.

A good example how to not write performance sensitive code, in general, and specifically in Java, would be Minecraft. Though commercially successful Minecraft is (or at least was) an excellent study of how to not do stuff, be it memory management, networking or rendering (when I played Minecraft it still used immediate mode GL if I recall correctly)