1、jps 列出JVM 进程
其中： -m 列出输入参数；-l 列出类全名 ；-v 列出JVM 参数
命令： jps -l
输出：
10664 org/netbeans/Main 7164 D:\Install\eclipse\\plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.jar 21124 sun.tools.jps.Jps
命令：jps -l -m -v
10664 org/netbeans/Main --branding visualvm --cachedir C:\Users\Hui\AppData\Local\VisualVM\Cache/7u14 -Xms24m -Xmx256m -XX:MaxPermSize=96m -Dsun.jvmstat.perdata.syncWaitMs=10000 -Dsun.java2d.noddraw=t rue -Dsun.java2d.d3d=false -Dnetbeans.keyring.no.master=true -Djdk.home=C:\Program Files\Java\jdk1.7.0_45 -Dnetbeans.home=C:\Program Files\Java\jdk1.7.0_45\lib\visualvm\platform -Dnetbeans.user=C:\Use rs\Hui\AppData\Roaming\VisualVM\7u14 -Dnetbeans.default_userdir_root=C:\Users\Hui\AppData\Roaming\VisualVM -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=C:\Users\Hui\AppData\Roaming\VisualVM\7u14\v ar\log\heapdump.hprof -Dnetbeans.system_http_proxy=DIRECT -Dsun.awt.keepWorkingSetOnMinimize=true -Dnetbeans.dirs=C:\Program Files\Java\jdk1.7.0_45\lib\visualvm\visualvm;C:\Program Files\Java\jdk1.7.0 _45\lib\visualvm\profiler
7164 D:\Install\eclipse\\plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.jar -os win32 -ws win32 -arch x86_64 -showsplash -launcher D:\Install\eclipse\eclipse.exe -name Eclipse --launcher.library D:\Install\eclipse\\plugins/org.eclipse.equinox.launcher.win32.win32.x86_64_1.1.100.v20110502\eclipse_1406.dll -startup D:\Install\eclipse\\plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.jar -- launcher.overrideVmargs -exitdata 1b4c_5c -vm C:\Windows\system32\javaw.exe -vmargs -Xms40m -Xmx384m -XX:MaxPermSize=256m -jar D:\Install\eclipse\\plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.
2、jstat 列出JVM统计信息
命令： jstat -gc 7164 250 20 （获取进程7164的Heap 状况，250毫秒为间隔，共获取20次）
输出：
S0C S1C S0U S1U EC EU OC OU PC PU YGC YGCT FGC FGCT GCT 9216.0 11264.0 4365.6 0.0 63488.0 58064.2 188416.0 121580.2 99328.0 92369.0 228 16.253 80 13.002 29.255 9216.0 11264.0 4365.6 0.0 63488.0 58064.2 188416.0 121580.2 99328.0 92369.0 228 16.253 80 13.002 29.255 9216.0 11264.0 4365.6 0.0 63488.0 58064.2 188416.0 121580.2 99328.0 92369.0 228 16.253 80 13.002 29.255 ......
其中：
S0C：Survivor0 区的容量
S0U：Survivor0 区的已使用容量
S1C：Survivor1 区的容量
S1U：Survivor1 区的已使用容量
EC：Eden 区的容量
EU：Eden 区的已使用容量
OC：Old 区的容量
OU：Old 区的已使用容量
PC：Perm 区的容量
PU：Perm 区的已使用容量
YGC：Yong GC次数
YGCT：Young GC总耗时
FGC: Full GC次数
FGCT: Full GC总耗时
GCT: GC总耗时
命令： jstat -class 7164 250 20 （ Class 状况 ）
Loaded Bytes Unloaded Bytes Time 14608 32709.6 10 13.4 48.15 14608 32709.6 10 13.4 48.15 14608 32709.6 10 13.4 48.15
命令： jstat -gccapacity 7164
NGCMN NGCMX NGC S0C S1C EC OGCMN OGCMX OGC OC PGCMN PGCMX PGC PC YGC FGC 13824.0 131072.0 82944.0 10752.0 4608.0 61440.0 27648.0 262144.0 188416.0 188416.0 21504.0 262144.0 99328.0 99328.0 229 80
命令：jstat -gcutil 7164
S0 S1 E O P YGC YGCT FGC FGCT GCT 0.00 90.85 1.63 64.64 92.99 229 16.280 80 13.002 29.282
命令：jstat -gcnew 7164
S0C S1C S0U S1U TT MTT DSS EC EU YGC YGCT 10752.0 4608.0 0.0 4186.2 15 15 10752.0 61440.0 1003.6 229 16.280
命令：jstat -gcnewcapacity 7164
NGCMN NGCMX NGC S0CMX S0C S1CMX S1C ECMX EC YGC FGC 13824.0 131072.0 82944.0 43520.0 10752.0 43520.0 4608.0 130048.0 61440.0 229 80
命令：jstat -gcold 7164
PC PU OC OU YGC FGC FGCT GCT 99328.0 92369.0 188416.0 121795.7 229 80 13.002 29.282
命令：jstat -gcoldcapacity 7164
OGCMN OGCMX OGC OC YGC FGC FGCT GCT
27648.0 262144.0 188416.0 188416.0 229 80 13.002 29.282
命令：jstat -gcpermcapacity 7164
PGCMN PGCMX PGC PC YGC FGC FGCT GCT 21504.0 262144.0 99328.0 99328.0 229 80 13.002 29.282
3、jinfo 获取Java配置信息
主要用于获取隐藏的属性 （jps获取不到的时候）
例子：jps -v -m -l
输出：
25364 org.apache.zookeeper.server.quorum.QuorumPeerMain /opt/zookeeper-3.3.6/bin/../conf/zoo.cfg -Dzookeeper.log.dir=. -Dzookeeper.root.logger=INFO,CONSOLE -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.local.only=false 25196 sun.tools.jps.Jps -m -v -l -Dapplication.home=/opt/jdk1.7.0_40 -Xms8m
从上面输出得不到 MaxHeapSize
命令：jinfo -flag MaxHeapSize 25364
输出：
-XX:MaxHeapSize=4181721088
4、jmap Java内存映像工具
命令： jmap -finalizerinfo 25364 (获取等待Finalizer 等待执行 finalize 方法的对象)
Attaching to process ID 25364, please wait... Debugger attached successfully. Server compiler detected. JVM version is 24.0-b55 Number of objects pending for finalization: 0
命令：jmap -heap 15968 （获取Heap信息， 如回收器、参数、分布状况等）
输出：
Attaching to process ID 7563, please wait... Debugger attached successfully. Server compiler detected. JVM version is 24.0-b55 using parallel threads in the new generation. using thread-local object allocation. Concurrent Mark-Sweep GC Heap Configuration: MinHeapFreeRatio = 40 MaxHeapFreeRatio = 70 MaxHeapSize = 3221225472 (3072.0MB) NewSize = 1310720 (1.25MB) MaxNewSize = 17592186044415 MB OldSize = 5439488 (5.1875MB) NewRatio = 7 SurvivorRatio = 8 PermSize = 21757952 (20.75MB) MaxPermSize = 402653184 (384.0MB) G1HeapRegionSize = 0 (0.0MB) Heap Usage: New Generation (Eden + 1 Survivor Space): capacity = 362414080 (345.625MB) used = 247609248 (236.13858032226562MB) free = 114804832 (109.48641967773438MB) 68.322193221632% used Eden Space: capacity = 322174976 (307.25MB) used = 236940944 (225.96449279785156MB) free = 85234032 (81.28550720214844MB) 73.54417991793379% used From Space: capacity = 40239104 (38.375MB) used = 10668304 (10.174087524414062MB) free = 29570800 (28.200912475585938MB) 26.512280193912865% used To Space: capacity = 40239104 (38.375MB) used = 0 (0.0MB) free = 40239104 (38.375MB) 0.0% used concurrent mark-sweep generation: capacity = 2818572288 (2688.0MB) used = 622975672 (594.1158981323242MB) free = 2195596616 (2093.884101867676MB) 22.10252597218468% used Perm Generation: capacity = 161153024 (153.6875MB) used = 160926760 (153.47171783447266MB) free = 226264 (0.21578216552734375MB) 99.85959680160889% used 93969 interned Strings occupying 9871528 bytes.
命令：jmap -histo 15968 （获取Heap中对象统计信息）
输出：
num #instances #bytes class name ---------------------------------------------- 1: 1877050 336315944 [C 2: 905407 178686896 [B 3: 271119 39064248 <constMethodKlass> 4: 1612739 38705736 java.lang.String 5: 271119 34718608 <methodKlass> 6: 185035 31871016 [I 7: 27348 31331008 <constantPoolKlass> 8: 529918 27000872 [Ljava.lang.Object; 9: 781241 24999712 java.util.HashMap$Entry 10: 264613 24359256 [Ljava.util.HashMap$Entry; 11: 26743 19538464 <instanceKlassKlass> 12: 22397 17551840 <constantPoolCacheKlass> 13: 579900 13917600 java.util.ArrayList 14: 171348 13707840 java.lang.reflect.Method 15: 271239 13019472 java.util.HashMap 16: 290856 11634240 java.util.LinkedHashMap$Entry 17: 261992 10479680 java.util.TreeMap$Entry 18: 391826 9403824 java.lang.Long 19: 201049 6433568 java.util.concurrent.ConcurrentHashMap$HashEntry 20: 9347 5358408 <methodDataKlass> 21: 98130 4710240 com.sun.tools.javac.file.ZipFileIndex$Entry 22: 40618 4556208 [[B 23: 70504 3948224 java.util.LinkedHashMap 24: 116683 3457816 [Ljava.lang.String; 25: 61713 3455928 org.hibernate.engine.EntityEntry .............................
命令：jmap -permstat 15968 （获取持久代中对象统计信息）
输出：
Attaching to process ID 15968, please wait... Debugger attached successfully. Server compiler detected. JVM version is 24.0-b55 finding class loader instances ..done. computing per loader stat ..done. please wait.. computing liveness..............liveness analysis may be inaccurate ... class_loader classes bytes parent_loader alive? type <bootstrap> 1199 7151168 null live <internal> 0x00000000e0108c80 0 0 0x00000000e002e520 live java/util/ResourceBundle$RBClassLoader@0x00000000db45af08 0x00000000e002e520 743 4624072 0x00000000e002e570 live sun/misc/Launcher$AppClassLoader@0x00000000db00b988 0x00000000e0033738 1 3024 null dead sun/reflect/DelegatingClassLoader@0x00000000dae4f480 0x00000000e002e570 0 0 null live sun/misc/Launcher$ExtClassLoader@0x00000000daf9fed0 total = 5 1943 11778264 N/A alive=4, dead=1 N/A
命令： jmap -dump:file=pib_7563 7563 （生成Heap Dump文件）
输出：
Dumping heap to /opt/phoenix/bin/pib_7563 ... Heap dump file created
[admin@VA128 ~]$ ll pib_7563 -rw------- 1 admin admin 849926091 Dec 23 10:22 pib_7563
5、jhat Heap Dump 文件分析工具
命令：jhat pib_15968.bin
输出：
Reading from pid_15968.bin... Dump file created Tue Dec 23 10:27:40 CST 2014 Snapshot read, resolving... Resolving 316796 objects... Chasing references, expect 63 dots............................................................... Eliminating duplicate references............................................................... Snapshot resolved. Started HTTP server on port 7000 Server is ready.
在浏览器：http://10.1.20.43:7000/ 可以查看
6、jstack
生成线程快照。参数 -l 显示锁；-m 显示Native方法；-F 强制。
命令： jstack -l 15968
输出：无锁
2014-12-23 10:32:26 Full thread dump Java HotSpot(TM) 64-Bit Server VM (24.0-b55 mixed mode): "Attach Listener" daemon prio=10 tid=0x00007f3250001000 nid=0x28d5 waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE Locked ownable synchronizers: - None "Thread-9" prio=10 tid=0x00007f3298475800 nid=0x3eec runnable [0x00007f327aaaa000] java.lang.Thread.State: RUNNABLE at java.io.FileInputStream.readBytes(Native Method) at java.io.FileInputStream.read(FileInputStream.java:272) at java.io.BufferedInputStream.fill(BufferedInputStream.java:235) at java.io.BufferedInputStream.read(BufferedInputStream.java:254) - locked <0x00000000e0008918> (a java.io.BufferedInputStream) at com.ph.phoenix.agent.AgentController.getLine(AgentController.java:57) at com.ph.phoenix.agent.AgentController.getCommand(AgentController.java:50) at com.ph.phoenix.agent.AgentController.run(AgentController.java:102) at java.lang.Thread.run(Thread.java:724) Locked ownable synchronizers: - None "Thread-8" prio=10 tid=0x00007f329845a800 nid=0x3eeb waiting on condition [0x00007f327abab000] java.lang.Thread.State: TIMED_WAITING (sleeping) at java.lang.Thread.sleep(Native Method) at com.ph.phoenix.agent.AgentJobManager.run(AgentJobManager.java:277) at java.lang.Thread.run(Thread.java:724) Locked ownable synchronizers: - None "Thread-7" daemon prio=10 tid=0x00007f3298458800 nid=0x3eea waiting on condition [0x00007f327acac000] java.lang.Thread.State: TIMED_WAITING (sleeping) at java.lang.Thread.sleep(Native Method) at com.ph.phoenix.agent.AgentJobExecutor.rest(AgentJobExecutor.java:123) at com.ph.phoenix.agent.AgentJobExecutor.run(AgentJobExecutor.java:144) at java.lang.Thread.run(Thread.java:724) Locked ownable synchronizers: - None ...............................................................................................
命令：jstack -l 7563
输出： 有锁
................................. "Grizzly-kernel-thread(1)" daemon prio=10 tid=0x00007f6658001800 nid=0x1df2 in Object.wait() [0x00007f6699d5c000] java.lang.Thread.State: TIMED_WAITING (on object monitor) at java.lang.Object.wait(Native Method) at com.sun.grizzly.Controller.waitUntilSelectorHandlersStop(Controller.java:1119)- locked <0x0000000740133438> (a java.util.concurrent.atomic.AtomicInteger) at com.sun.grizzly.ReadController.start(ReadController.java:121) at com.sun.grizzly.Controller.run(Controller.java:709) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:724) Locked ownable synchronizers:- <0x000000074013b4b0> (a java.util.concurrent.ThreadPoolExecutor$Worker) .................................
死锁检测
命令：jstack -l 15436
输出： 有死锁
- None
"79_A" prio=6 tid=0x000000000a449000 nid=0x1748 waiting for monitor entry [0x000
000000d32f000]
java.lang.Thread.State: BLOCKED (on object monitor)
at jconsole.DeadLockTest$SyncTask.run(DeadLockTest.java:17)
- waiting to lock <0x00000000ec900bb8> (a java.lang.Object)
at java.lang.Thread.run(Unknown Source)
Locked ownable synchronizers:
- None
"78_B" prio=6 tid=0x000000000a414000 nid=0x3b24 waiting for monitor entry [0x000
000000c13f000]
java.lang.Thread.State: BLOCKED (on object monitor)
at jconsole.DeadLockTest$SyncTask.run(DeadLockTest.java:18)
- waiting to lock <0x00000000ec900bb8> (a java.lang.Object)
- locked <0x00000000ec9007f0> (a java.lang.Object)
at java.lang.Thread.run(Unknown Source)
Locked ownable synchronizers:
- None
"78_A" prio=6 tid=0x000000000a422800 nid=0x3848 waiting for monitor entry [0x000
000000b86f000]
java.lang.Thread.State: BLOCKED (on object monitor)
at jconsole.DeadLockTest$SyncTask.run(DeadLockTest.java:18)
- waiting to lock <0x00000000ec9007f0> (a java.lang.Object)
- locked <0x00000000ec900bb8> (a java.lang.Object)
at java.lang.Thread.run(Unknown Source)
Locked ownable synchronizers:
- None
"77_B" prio=6 tid=0x000000000a415800 nid=0x780 waiting for monitor entry [0x0000
00000c5bf000]
java.lang.Thread.State: BLOCKED (on object monitor)
at jconsole.DeadLockTest$SyncTask.run(DeadLockTest.java:17)
- waiting to lock <0x00000000ec9007f0> (a java.lang.Object)
at java.lang.Thread.run(Unknown Source)
Locked ownable synchronizers:
- None
"77_A" prio=6 tid=0x000000000a41e000 nid=0x315c waiting for monitor entry [0x000
000000b69f000]
java.lang.Thread.State: BLOCKED (on object monitor)
at jconsole.DeadLockTest$SyncTask.run(DeadLockTest.java:17)
- waiting to lock <0x00000000ec900bb8> (a java.lang.Object)
at java.lang.Thread.run(Unknown Source)
Locked ownable synchronizers:
- None
。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。
JNI global references: 107
Found one Java-level deadlock:
=============================
"99_B":
waiting to lock monitor 0x0000000008684e68 (object 0x00000000ec9007f0, a java.
lang.Object),
which is held by "78_B"
"78_B":
waiting to lock monitor 0x000000000a3e34c8 (object 0x00000000ec900bb8, a java.
lang.Object),
which is held by "78_A"
"78_A":
waiting to lock monitor 0x0000000008684e68 (object 0x00000000ec9007f0, a java.
lang.Object),
which is held by "78_B"
Java stack information for the threads listed above:
===================================================
"99_B":
at jconsole.DeadLockTest$SyncTask.run(DeadLockTest.java:17)
- waiting to lock <0x00000000ec9007f0> (a java.lang.Object)
at java.lang.Thread.run(Unknown Source)
"78_B":
at jconsole.DeadLockTest$SyncTask.run(DeadLockTest.java:18)
- waiting to lock <0x00000000ec900bb8> (a java.lang.Object)
- locked <0x00000000ec9007f0> (a java.lang.Object)
at java.lang.Thread.run(Unknown Source)
"78_A":
at jconsole.DeadLockTest$SyncTask.run(DeadLockTest.java:18)
- waiting to lock <0x00000000ec9007f0> (a java.lang.Object)
- locked <0x00000000ec900bb8> (a java.lang.Object)
at java.lang.Thread.run(Unknown Source)
Found 1 deadlock.
7、JConsole
(1). 内存测试
配置：
-Xms100M -Xmx100M -XX:+UseSerialGC
代码：
static class OOMObject
{
public byte[] placeholder = new byte[64*1024];
}
public static void main(String[] args) throws InterruptedException {
List<OOMObject> list = new LinkedList<OOMObject>();
for(int i=0;i<1000;i++)
{
Thread.sleep(50);
list.add(new OOMObject());
}
System.gc();
}
效果：
可查看总的Heap、非Heap、Eden、Survivor、Tenured、Perm、Code Cache 情况
(2). 线程测试
代码：
public static void createBusyThread() {
Thread t = new Thread(new Runnable() {
@Override
public void run() {
while (true)
;
}
}, " Busy Thread");
t.start();
}
public static void createLockThread(final Object lock) {
Thread t = new Thread(new Runnable() {
@Override
public void run() {
synchronized (lock) {
try {
lock.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}, " Lock Thread");
t.start();
}
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
br.readLine();
createBusyThread();
br.readLine();
createLockThread(new Object());
}
结果：
(3).死锁检测
代码：
static class SyncTask implements Runnable {
Object a;
Object b;
public SyncTask(Object a, Object b) {
this.a = a;
this.b = b;
}
@Override
public void run() {
synchronized (a) {
synchronized (b) {
System.out.println(Thread.currentThread().getName());
}
}
}
}
public static void main(String[] args) {
Object o1 = new Object();
Object o2 = new Object();
for (int i = 0; i < 100; i++) {
new Thread(new SyncTask(o1, o2), i+"_A").start();
new Thread(new SyncTask(o2, o1), i+"_B").start();
}
}
结果：
8、VisualVM
可生成Heap Dump、Thread Dump。可装入Dump 文件进行分析。
可监控CPU、Heap、Thread 等资源的动态运行情况。