启动jvm时加上一些参数即可

常用参数：
<code>
java \
-Xmx4G \
-XX:+UseG1GC \
-XX:MaxGCPauseMillis=200 \
-XX:ConcGCThreads=2 \
-XX:+PrintGC \
-XX:+PrintHeapAtGC \
-XX:+PrintGCDetails \
-XX:+PrintGCTimeStamps \
-XX:+HeapDumpOnOutOfMemoryError \
-XX:+PrintGCApplicationStoppedTime  \
-Xloggc:gc.log \
-XX:OnError="echo error" \
-XX:OnOutOfMemoryError="echo OnOutOfMemoryError" \
</code>


日志输出：
2016-07-28T10:44:39.345-0800: 6.282: [GC [PSYoungGen: 34320K->496K(38912K)] 34328K->504K(125952K), 0.0021030 secs] [Times: user=0.00 sys=0.00, real=0.00 secs] 

  * 0.0021030 secs <color red>(gc耗时)</color>
  * PSYoungGen <color red>(young gc)</color>