In Ranch use the search facility and search with keyword garbage collection and author Jim Yingst. All his replies have excellent content and very valuable for exam. Pls tell afterwards whether u still need anything else. for GC no book is good. Use ranch only. tvs sundaram SCP for Java2 Platform
i think there will be few about gc. the things i need to remember is only the instances which are no longer refered by any reference MAY be collected. but there is nothing can guarantee whether or when this will happen, even the call to System.gc() and Runtime.gc().