Elasticsearch version (bin/elasticsearch --version):
Plugins installed: 
JVM version (java -version):
OS version (uname -a if on a Unix-like system):
Linux localhost.localdomain 3.10.0-229.el7.x86_64 #1 SMP Fri Mar 6 11:36:42 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
Description of the problem including expected versus actual behavior:
We are running a one node elaticsearch cluster with 32GB heap size . The heap size is continous increasing even if there are no any indexing and query, so what is increasing in the heap? Is it a bug or it's normal for jvm?
see the img below from x-pack for detail jvm and index info.