JDK1.8をcentosに入れて、デフォルトのjavaを入れ替える で jstatで監視

jstatを使ってヒープの監視がしたかったのでいれる。

このサイトの通りでいけた。
How to Install Java 8 (Jdk 8u31) on CentOS/RHEL 7/6/5

cd /opt/
wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/8u31-b13/jdk-8u31-linux-x64.tar.gz"
tar xzf jdk-8u31-linux-x64.tar.gz

cd /opt/jdk1.8.0_31/
alternatives --install /usr/bin/java java /opt/jdk1.8.0_31/bin/java 2
# alternatives --config java
alternatives --config java

alternatives --install /usr/bin/jar jar /opt/jdk1.8.0_31/bin/jar 2
alternatives --install /usr/bin/javac javac /opt/jdk1.8.0_31/bin/javac 2
alternatives --set jar /opt/jdk1.8.0_31/bin/jar
alternatives --set javac /opt/jdk1.8.0_31/bin/javac

### check
java -version
# java version "1.8.0_31"
# Java(TM) SE Runtime Environment (build 1.8.0_31-b13)
# Java HotSpot(TM) 64-Bit Server VM (build 25.31-b07, mixed mode)

###
vim /etc/bashrc
===============
export JAVA_HOME=/opt/jdk1.8.0_31
export JRE_HOME=/opt/jdk1.8.0_31/jre
export PATH=$PATH:/opt/jdk1.8.0_31/bin:/opt/jdk1.8.0_31/jre/bin
===============

jstatでメモリの使用率を監視

# 調べたいプロセスのIDを調べる
jps -v

# 5秒に一回監視
jstat -gcutil -t ${TARGET_PID} 5000