Company blog of Plumbr, a Java monitoring tool vendor, covering memory leaks, garbage collection, and startup experience.
HN commenters link its handbook on Java garbage collection as a comprehensive explanation, and its seed round announcement.
Here is a pretty comprehensive article on the java garbage collector: https://plumbr.eu/handbook/garbage-collection-in-java that has helped me a lot.
It touches the basic aspects of garbage collecting, and dives into the different kinds of GC available for java at this time.
As covered in the company blog: http://plumbr.eu/blog/happy-to-announce-a-1m-seed-round