In my experience, memory leaks in GC languages are very easy to track down, since the timing for analyzing the heap is excellent. While discovering that you do have a memory leak is not very easy, once you know about it you can easily compare heap snapshots, find the increasing objects, and track down their GC roots, all from the same tool. With Java especially, you can even do this on a running service in production, with minimal downtime.
In contrast, it's much harder to track down memory leaks in C, since the runtime has little information about the contents of the heap. You typically end up using valgrind to instrument your code, assuming it can still run fast enough to reproduce the problem.
The only exception is Go, which has awful tooling for analyzing memory. For some bizarre reason, it can't even show you the gc roots of an object in memory, even though the GC obviously needs this information to work properly.
