java 性能监控 jstack 线程死锁 JConsole 和 BTrace 图形化工具

java 性能监控 工具

除了 javac java javap 之外, jdk 安装包还提供了很多其他工具
列出 bin 目录下的文件

TomChens-MacBook-Pro:Commands tomchen$ ls
appletviewer    javadoc     jmap        keytool     serialver
apt     javah       jmc     native2ascii    servertool
extcheck    javap       jps     orbd        tnameserv
idlj        javaws      jrunscript  pack200     unpack200
jar     jcmd        jsadebugd   policytool  wsgen
jarsigner   jconsole    jstack      rmic        wsimport
java        jdb     jstat       rmid        xjc
java_home   jhat        jstatd      rmiregistry
javac       jinfo       jvisualvm   schemagen

jvisualvm

可以在线安装很多插件, 这是最新的非常强大的多合一故障处理工具

生成 Heap Dump, 可以在OQL Console 执行类似 sql 语句的 OQL

jvisualvm 的 BTrace 插件

生产环境服务无法停止的时候, 而日志里的信息无法满足我们需要时候, 可以通过这个打印调用堆栈 参数 返回值等

jconsole

也是一个图形化的监控工具

jps 虚拟机进程状况工具

类似于 ps 命令

jps -l
582 HttpFind
431 RefreshBlog.jar
585 sun.tools.jps.Jps

jstat 虚拟机统计信息监控工具

 jstat -gcutil 431
  S0     S1     E      O      P     YGC     YGCT    FGC    FGCT     GCT   
  0.00  57.17  12.43  24.74  42.31     13    0.044     0    0.000    0.044

从中可以看出 survivor(S0 S1) eden (E) young GC(YGC) 等参数

jstat -class 434
Loaded  Bytes  Unloaded  Bytes     Time   
 17095 36897.7     1899  2970.9      14.87

类加载时间为14.87

jstack java堆栈管理工具

可以查看线程死锁

jstack 582
......
......
Found one Java-level deadlock:
=============================
"Thread-199":
  waiting to lock monitor 0x00007facb3027608 (object 0x00000007e786b528, a java.lang.Integer),
  which is held by "Thread-3"
"Thread-3":
  waiting to lock monitor 0x00007facb3026108 (object 0x00000007e786b518, a java.lang.Integer),
  which is held by "Thread-8"
"Thread-8":
  waiting to lock monitor 0x00007facb3027608 (object 0x00000007e786b528, a java.lang.Integer),
  which is held by "Thread-3"

Java stack information for the threads listed above:
===================================================
"Thread-199":
    at HttpFind$SyncAdd.run(HttpFind.java:52)
    - waiting to lock <0x00000007e786b528> (a java.lang.Integer)
    at java.lang.Thread.run(Thread.java:722)
"Thread-3":
    at HttpFind$SyncAdd.run(HttpFind.java:53)
    - waiting to lock <0x00000007e786b518> (a java.lang.Integer)
    - locked <0x00000007e786b528> (a java.lang.Integer)
    at java.lang.Thread.run(Thread.java:722)
"Thread-8":
    at HttpFind$SyncAdd.run(HttpFind.java:53)
    - waiting to lock <0x00000007e786b528> (a java.lang.Integer)
    - locked <0x00000007e786b518> (a java.lang.Integer)
    at java.lang.Thread.run(Thread.java:722)

Found 1 deadlock.

jhat 虚拟机堆转储快照分析工具

jinfo java 配置信息工具

jmap java 内存印象工具