ABSTRACT   In Java, allocation and deallocation of heap memory are handled by the virtual machine, i.e., by its memory manager and its garbage collector.  This concept frees developers from the chores of explicit memory allocation and deallocation and eliminates the pitfalls that explicit memory management comes with, e.g. there are no memory leaks or dangling pointers in Java.  Despite of this undeniable benefit, Java programs occasionally exhibit performance defects that are caused by excessive memory allocation or massive and time-consuming garbage collection.  In order to eliminate these adverse effects on the program's overall performance, a Java developer needs an understanding of the memory allocation and garbage collection strategies of the JVM. The tutorial gives an overview of various garbage collection algorithms employed by the Java virtual machine of Sun's JDK 6 including the novel “Garbage First” (G1) collector along with tips and tricks for tuning the garbage collector, use of memory profilers and garbage collection profilers.

Level:	introductory
Duration:	~ 90 minutes
Prerequisite:	basic Java knowledge
Presented at:	JUGS Event 2009 , Bern, Switzerland, Dec 14, 2009 JAX 2010 , Mainz, Germany, May 3-7, 2010 ruhrJUG , Essen, Germany, August 2, 2010