$ jps
4866 Bootstrap
5944 Jps
5773 Main
得到tomcat进程id 4866
$ jmap -dump:format=b,file=d.hprof 4866
Dumping heap to /usr/local/tomcat/d.hprof ...
Heap dump file created
dump内存信息
jvisualvm 加载 d.hprof文件
也可用以下指令
$ jmap -histo 4866
num #instances #bytes class name
----------------------------------------------
1: 146801 16675856 [C
2: 36009 10521128 [B
3: 59949 8609384 <constMethodKlass>
4: 59949 7684736 <methodKlass>
5: 5770 6616336 <constantPoolKlass>
6: 180992 6278528 [Ljava.lang.Object;
7: 14729 5149584 [I
8: 5770 4095904 <instanceKlassKlass>
9: 4835 3674240 <constantPoolCacheKlass>
10: 120051 2881224 java.lang.String
11: 78037 2497184 java.io.ObjectStreamClass$WeakClassKey
12: 61747 2469880 java.util.TreeMap$Entry
13: 19919 1593520 java.lang.reflect.Method
14: 1910 1033968 <methodDataKlass>
15: 20195 646240 java.util.HashMap$Entry
16: 25967 623208 java.lang.Long
17: 6255 603744 java.lang.Class
18: 5960 593080 [Ljava.util.HashMap$Entry;
19: 5700 592800 java.io.ObjectStreamClass
20: 17048 545536 java.util.concurrent.ConcurrentHashMap$HashEntry
21: 8191 495288 [S
22: 10022 481056 java.util.HashMap
23: 9450 469488 [[I
24: 14434 461888 java.util.TreeMap$KeyIterator
25: 10798 431920 java.util.LinkedHashMap$Entry
26: 14557 349368 java.util.ArrayList
27: 5409 346176 java.net.URL
28: 14843 336312 [Ljava.lang.Class;
29: 6632 318336 java.util.TreeMap
30: 11531 276744 java.lang.StringBuilder
31: 2850 273600 java.lang.management.ThreadInfo
32: 6768 270720 com.sun.org.apache.xerces.internal.dom.DeferredTextImpl
33: 468 254592 <objArrayKlassKlass>
34: 7879 252128 java.util.TreeMap$EntryIterator
35: 6094 243760 com.sun.org.apache.xerces.internal.dom.DeferredAttrImpl
36: 4270 239120 java.util.LinkedHashMap
37: 6130 233472 [Ljava.lang.String;
38: 9532 228768 java.io.SerialCallbackContext
39: 6546 209472 java.lang.ref.WeakReference
40: 3651 204456 com.sun.org.apache.xerces.internal.dom.DeferredElementImpl
41: 7837 188088 java.util.Collections$UnmodifiableCollection$1
42: 1493 182000 [Ljava.util.concurrent.ConcurrentHashMap$HashEntry;
43: 2503 180216 java.lang.reflect.Field
44: 3678 176544 org.apache.catalina.loader.ResourceEntry
45: 8713 171336 [Ljavax.management.openmbean.CompositeData;
46: 6597 158328 javax.management.openmbean.CompositeDataSupport
47: 3274 157152 org.aspectj.weaver.reflect.ShadowMatchImpl
48: 8226 131616 java.lang.Boolean
49: 3241 129640 java.lang.ref.SoftReference
50: 3614 124392 [Ljavax.management.ObjectName$Property;
。。。手动触发GC
$ jcmd 4866 GC.run
4866:
Command executed successfully