Always Full GC before Dump

1. Environment

Windows 7 64-bit, JDK 1.7, jvisualvm

2. Problem

Every time I push the HEAP DUMP button in jvisualvm, the JVM always conducts a full GC before dumping, so I can't see all objects before GC.

3. Analysis

3.1 Full Collection VS Young Collection

or in terms of minor collection, major collection, full collection

3.2 why GC before dumping

A good answer from stack overflow:

4. Solution

Reference:

[1] http://stackoverflow.com/questions/1268336/how-can-i-take-a-heap-dump-on-java-5-without-garbage-collecting-first

[2] Manning, the well-grounded Java Developer.

[3] http://stackoverflow.com/questions/5403161/can-jvisualvm-heap-dump-button-release-memory

[4] http://www.cubrid.org/blog/dev-platform/understanding-java-garbage-collection/  (strongly recommended!)