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yzs5273:
没什么用。都试过了
WIN7下CS不能全屏的解决方法 -
di1984HIT:
不错,学习了
读取本地计算机中的安装程序列表 -
ffedu:
[flash=200,200][url][img][list] ...
linux/unix中如何用find命令详解,非常详细的介绍,比man find强100倍(转) -
lintghi:
...
Log4j使用相对路径指定log文件及使用总结 -
nick.s.ni:
唉,Java中引用的包没有介绍啊,如果数据库用UTF-8的格式 ...
Oracle 中Java 对象与PL/SQL类型的映射及使用(转)
1.jinfo
描述:输出给定 java 进程所有的配置信息。包括 java 系统属性和 jvm 命令行标记等。
用法:
jinfo [ option ] pid
jinfo [ option ] executable core
jinfo [ option ] [server-id@]remote-hostname-or-IP
例子:
jinfo pid
得到结果如下:
- JVM version is 14.0-b16
- Java System Properties:
- java.runtime.name = Java(TM) SE Runtime Environment
- sun.boot.library.path = /work/ProgramFiles/jdk1.6.0_14/jre/lib/i386
- java.vm.version = 14.0-b16
- java.vm.vendor = Sun Microsystems Inc.
- java.vendor.url = http://java.sun.com/
- path.separator = :
- java.vm.name = Java HotSpot(TM) Server VM
- file.encoding.pkg = sun.io
- sun.java.launcher = SUN_STANDARD
- user.country = CN
- sun.os.patch.level = unknown
- java.vm.specification.name = Java Virtual Machine Specification
- user.dir = /work/RateWorkspace/branches/rate/daemon
- java.runtime.version = 1.6.0_14-b08
- java.awt.graphicsenv = sun.awt.X11GraphicsEnvironment
- java.endorsed.dirs = /work/ProgramFiles/jdk1.6.0_14/jre/lib/endorsed
- os.arch = i386
- java.io.tmpdir = /tmp
- line.separator =
- java.vm.specification.vendor = Sun Microsystems Inc.
- os.name = Linux
- sun.jnu.encoding = UTF-8
- java.library.path = /work/ProgramFiles/jdk1.6.0_14/jre/lib/i386/server:/work/ProgramFiles/jdk1.6.0_14/jre/lib/i386:/work/ProgramFiles/jdk1.6.0_14/jre/../lib/i386:/usr/lib/jvm/java-6-openjdk/jre/lib/i386/client:/usr/lib/jvm/java-6-openjdk/jre/lib/i386:/usr/lib/xulrunner-addons:/usr/lib/xulrunner-addons:/usr/java/packages/lib/i386:/lib:/usr/lib
- java.specification.name = Java Platform API Specification
- java.class.version = 50.0
- sun.management.compiler = HotSpot Tiered Compilers
- os.version = 2.6.28-19-generic
- user.home = /home/yblin
- user.timezone = PRC
- java.awt.printerjob = sun.print.PSPrinterJob
- file.encoding = GBK
- java.specification.version = 1.6
- java.class.path =
- user.name = yblin
- java.vm.specification.version = 1.0
- java.home = /work/ProgramFiles/jdk1.6.0_14/jre
- sun.arch.data.model = 32
- user.language = zh
- java.specification.vendor = Sun Microsystems Inc.
- java.vm.info = mixed mode
- java.version = 1.6.0_14
- java.ext.dirs = /work/ProgramFiles/jdk1.6.0_14/jre/lib/ext:/usr/java/packages/lib/ext
- sun.boot.class.path = /work/ProgramFiles/jdk1.6.0_14/jre/lib/resources.jar:/work/ProgramFiles/jdk1.6.0_14/jre/lib/rt.jar:/work/ProgramFiles/jdk1.6.0_14/jre/lib/sunrsasign.jar:/work/ProgramFiles/jdk1.6.0_14/jre/lib/jsse.jar:/work/ProgramFiles/jdk1.6.0_14/jre/lib/jce.jar:/work/ProgramFiles/jdk1.6.0_14/jre/lib/charsets.jar:/work/ProgramFiles/jdk1.6.0_14/jre/classes
- java.vendor = Sun Microsystems Inc.
- file.separator = /
- java.vendor.url.bug = http://java.sun.com/cgi-bin/bugreport.cgi
- sun.io.unicode.encoding = UnicodeLittle
- sun.cpu.endian = little
- sun.desktop = gnome
- sun.cpu.isalist =
- VM Flags:
- -agentlib:jdwp=transport=dt_socket,suspend=y,address=localhost:55948 -ea -Dfile.encoding=GBK
JVM version is 14.0-b16 Java System Properties: java.runtime.name = Java(TM) SE Runtime Environment sun.boot.library.path = /work/ProgramFiles/jdk1.6.0_14/jre/lib/i386 java.vm.version = 14.0-b16 java.vm.vendor = Sun Microsystems Inc. java.vendor.url = http://java.sun.com/ path.separator = : java.vm.name = Java HotSpot(TM) Server VM file.encoding.pkg = sun.io sun.java.launcher = SUN_STANDARD user.country = CN sun.os.patch.level = unknown java.vm.specification.name = Java Virtual Machine Specification user.dir = /work/RateWorkspace/branches/rate/daemon java.runtime.version = 1.6.0_14-b08 java.awt.graphicsenv = sun.awt.X11GraphicsEnvironment java.endorsed.dirs = /work/ProgramFiles/jdk1.6.0_14/jre/lib/endorsed os.arch = i386 java.io.tmpdir = /tmp line.separator = java.vm.specification.vendor = Sun Microsystems Inc. os.name = Linux sun.jnu.encoding = UTF-8 java.library.path = /work/ProgramFiles/jdk1.6.0_14/jre/lib/i386/server:/work/ProgramFiles/jdk1.6.0_14/jre/lib/i386:/work/ProgramFiles/jdk1.6.0_14/jre/../lib/i386:/usr/lib/jvm/java-6-openjdk/jre/lib/i386/client:/usr/lib/jvm/java-6-openjdk/jre/lib/i386:/usr/lib/xulrunner-addons:/usr/lib/xulrunner-addons:/usr/java/packages/lib/i386:/lib:/usr/lib java.specification.name = Java Platform API Specification java.class.version = 50.0 sun.management.compiler = HotSpot Tiered Compilers os.version = 2.6.28-19-generic user.home = /home/yblin user.timezone = PRC java.awt.printerjob = sun.print.PSPrinterJob file.encoding = GBK java.specification.version = 1.6 java.class.path = user.name = yblin java.vm.specification.version = 1.0 java.home = /work/ProgramFiles/jdk1.6.0_14/jre sun.arch.data.model = 32 user.language = zh java.specification.vendor = Sun Microsystems Inc. java.vm.info = mixed mode java.version = 1.6.0_14 java.ext.dirs = /work/ProgramFiles/jdk1.6.0_14/jre/lib/ext:/usr/java/packages/lib/ext sun.boot.class.path = /work/ProgramFiles/jdk1.6.0_14/jre/lib/resources.jar:/work/ProgramFiles/jdk1.6.0_14/jre/lib/rt.jar:/work/ProgramFiles/jdk1.6.0_14/jre/lib/sunrsasign.jar:/work/ProgramFiles/jdk1.6.0_14/jre/lib/jsse.jar:/work/ProgramFiles/jdk1.6.0_14/jre/lib/jce.jar:/work/ProgramFiles/jdk1.6.0_14/jre/lib/charsets.jar:/work/ProgramFiles/jdk1.6.0_14/jre/classes java.vendor = Sun Microsystems Inc. file.separator = / java.vendor.url.bug = http://java.sun.com/cgi-bin/bugreport.cgi sun.io.unicode.encoding = UnicodeLittle sun.cpu.endian = little sun.desktop = gnome sun.cpu.isalist = VM Flags: -agentlib:jdwp=transport=dt_socket,suspend=y,address=localhost:55948 -ea -Dfile.encoding=GBK
这个命令包含了 JDK 和 JVM 运行起来时的一些属性。
2.jmap
描述 :输出给定 java 进程所有的内存使用信息。
使用:
jmap [ option ] pid
jmap [ option ] executable core
jmap [ option ] [server-id@]remote-hostname-or-IP
<no option>
没有可选项时,会输出所有共享的对象映射。
开始地址,映射大小,全路径。
直接 jmap pid得到如下结果:
0x08048000 46K /work/ProgramFiles/jdk1.6.0_14/bin/java
0xb6763000 74K /work/ProgramFiles/jdk1.6.0_14/jre/lib/i386/libzip.so
0xb6774000 41K /lib/tls/i686/cmov/libnss_files-2.9.so
0xb6780000 37K /lib/tls/i686/cmov/libnss_nis-2.9.so
0xb678b000 29K /lib/tls/i686/cmov/libnss_compat-2.9.so
目前还说不是很理解这个执行结果是什么意思。经询问同事了解,是加载的文件的信息。
-heap 选项
jmap -heap pid : 查看堆的配置和大当前各个区块的使用情况,如伊甸区、老年代,永久代。可以用此来判断内存目前的使用情况以及垃圾回收情况:
jmap -heap pid,得到如下结果:
-histo 选项 内存使用的柱状图,包含每个类,对象使用的内存大小。 VM 内部的类名以 * 前缀开头。
-permstat 选项 输出所有类装载器在堆里产生的对象 包括每个装载器的名字,活跃,地址,父装载器,和其总共加载的类大小。 jmap -permstat pid 得到如下结果:
3.jstack - Stack Trace 为指定的线程输出 java 的线程堆栈信息,包括了进程里的所有线程。每一个线程 frame ,包括类全名,方法名,代码行。 java.lang.Thread.State : RUNNABLE BLOCKED TIMED_WATTING(sleep 后会进入这种状态 ) (如果是 BLOCKED 状态就要注意了,看看 blocked 的状态在等待什么?因为什么而阻塞?)最常见的情况是线程在等待网络的读写,比如当网络数据没有准备好读时,线程处于这种等待状态,而一旦有数据准备好读之后,线程会重新激活,读取并处理数据。 在线程中,有一些 JVM 内部的后台线程,来执行譬如垃圾回收,或者低内存的检测等等任务,这些线程往往在 JVM 初始化的时候就存在,如下所示: "Low Memory Detector" daemon prio=10 tid=0x081465f8 nid=0x7 runnable [0x00000000..0x00000000] "CompilerThread0" daemon prio=10 tid=0x08143c58 nid=0x6 waiting on condition [0x00000000..0xfb5fd798] "Signal Dispatcher" daemon prio=10 tid=0x08142f08 nid=0x5 waiting on condition [0x00000000..0x00000000] "Finalizer" daemon prio=10 tid=0x08137ca0 nid=0x4 in Object.wait() [0xfbeed000..0xfbeeddb8] 写了个代码, 100 个线程同时往控制台输出,代码如下:
通过 jstack pid, 得到如下部分结果:
可以看到只有线程 thrad75 是 RUNNABLE 状态的,其他的都是 BLOCKED 状态。因为其他的线程在竞争控制台输出的时候都被阻塞了。
num #instances #bytes class name
----------------------------------------------
1: 57195 5639792 [C
2: 34680 3991104 <constMethodKlass>
3: 34680 2779112 <methodKlass>
4: 52947 2340272 <symbolKlass>
5: 3024 1641744 <constantPoolKlass>
6: 5182 1618040 [B
7: 3024 1290544 <instanceKlassKlass>
8: 12134 1267696 [I
9: 44622 1070928 java.lang.String
10: 2565 994128 <constantPoolCacheKlass>
………………
class_loader classes bytes parent_loader alive? type
<bootstrap> 1102 4283352 null live <internal>
0x80753d50 1 1992 null dead sun/reflect/DelegatingClassLoader@0x7c2e6c28
0x8034d9e0 8 32272 null live sun/misc/Launcher$ExtClassLoader@0x7c432400
0x8095a4e0 1 1784 0x8034d998 dead sun/reflect/DelegatingClassLoader@0x7c2e6c28
0xadc25868 1 1784 0x8034d998 dead sun/reflect/DelegatingClassLoader@0x7c2e6c28
0xaebf74c0 1 1784 0x8034d998 dead sun/reflect/DelegatingClassLoader@0x7c2e6c28
0xadc2b5c8 1 1784 0x8034d998 dead sun/reflect/DelegatingClassLoader@0x7c2e6c28
0x808cd448 1 1768 0x8034d998 dead sun/reflect/DelegatingClassLoader@0x7c2e6c28
0x80758288 1 1768 0x8034d998 dead sun/reflect/DelegatingClassLoader@0x7c2e6c28
0x80959e80 1 1784 0x8034d998 dead sun/reflect/DelegatingClassLoader@0x7c2e6c28
0x80756248 1 1768 0x8034d998 dead sun/reflect/DelegatingClassLoader@0x7c2e6c28
0x808e6ae8 1 1784 0x8034d998 dead sun/reflect/DelegatingClassLoader@0x7c2e6c28
public class MyThread extends Thread {
public MyThread(String name){
super(name);
}
@Override
public void run() {
super.run();
while (true) {
try {
System.out.println("1");
} catch (Exception e) {
}
}
}
public static void main(String[] args) {
for (int i = 0; i < 100; i++) {
MyThread my = new MyThread("thrad" + i);
my.start();
}
}
}
"thrad76" prio=10 tid=0x096ce400 nid=0x4305 waiting for monitor entry [0x7a280000]
java.lang.Thread.State: BLOCKED (on object monitor)
at java.io.PrintStream.println(PrintStream.java:755)
- waiting to lock <0x805782c0> (a java.io.PrintStream)
at org.jtester.service.MyThread.run(MyThread.java:15)
"thrad75" prio=10 tid=0x096ccc00 nid=0x4304 runnable [0x7a2d1000]
java.lang.Thread.State: RUNNABLE
at java.io.PrintStream.write(PrintStream.java:428)
- locked <0x805782c0> (a java.io.PrintStream)
at sun.nio.cs.StreamEncoder.writeBytes(StreamEncoder.java:202)
at sun.nio.cs.StreamEncoder.implFlushBuffer(StreamEncoder.java:272)
at sun.nio.cs.StreamEncoder.flushBuffer(StreamEncoder.java:85)
- locked <0x805783c8> (a java.io.OutputStreamWriter)
at java.io.OutputStreamWriter.flushBuffer(OutputStreamWriter.java:168)
at java.io.PrintStream.write(PrintStream.java:477)
- locked <0x805782c0> (a java.io.PrintStream)
at java.io.PrintStream.print(PrintStream.java:619)
at java.io.PrintStream.println(PrintStream.java:756)
- locked <0x805782c0> (a java.io.PrintStream)
at org.jtester.service.MyThread.run(MyThread.java:15)
"thrad74" prio=10 tid=0x096cb000 nid=0x4303 waiting for monitor entry [0x7a322000]
java.lang.Thread.State: BLOCKED (on object monitor)
at java.io.PrintStream.println(PrintStream.java:755)
- waiting to lock <0x805782c0> (a java.io.PrintStream)
at org.jtester.service.MyThread.run(MyThread.java:15)
- Heap Configuration:
- MinHeapFreeRatio = 40
- MaxHeapFreeRatio = 70
- MaxHeapSize = 859832320 (820.0MB)
- NewSize = 1048576 (1.0MB)
- MaxNewSize = 4294901760 (4095.9375MB)
- OldSize = 4194304 (4.0MB)
- NewRatio = 8
- SurvivorRatio = 8
- PermSize = 16777216 (16.0MB)
- MaxPermSize = 67108864 (64.0MB)
- Heap Usage:
- PS Young Generation
- Eden Space:
- capacity = 9043968 (8.625MB)
- used = 6820384 (6.504425048828125MB)
- free = 2223584 (2.120574951171875MB)
- 75.41362375452898% used
- From Space:
- capacity = 720896 (0.6875MB)
- used = 704680 (0.6720352172851562MB)
- free = 16216 (0.01546478271484375MB)
- 97.7505770596591% used
- To Space:
- capacity = 720896 (0.6875MB)
- used = 0 (0.0MB)
- free = 720896 (0.6875MB)
- 0.0% used
- PS Old Generation
- capacity = 47710208 (45.5MB)
- used = 589184 (0.5618896484375MB)
- free = 47121024 (44.9381103515625MB)
- 1.2349223042582418% used
- PS Perm Generation
- capacity = 16777216 (16.0MB)
- used = 5179648 (4.939697265625MB)
- free = 11597568 (11.060302734375MB)
- 30.87310791015625% used
Heap Configuration: MinHeapFreeRatio = 40 MaxHeapFreeRatio = 70 MaxHeapSize = 859832320 (820.0MB) NewSize = 1048576 (1.0MB) MaxNewSize = 4294901760 (4095.9375MB) OldSize = 4194304 (4.0MB) NewRatio = 8 SurvivorRatio = 8 PermSize = 16777216 (16.0MB) MaxPermSize = 67108864 (64.0MB) Heap Usage: PS Young Generation Eden Space: capacity = 9043968 (8.625MB) used = 6820384 (6.504425048828125MB) free = 2223584 (2.120574951171875MB) 75.41362375452898% used From Space: capacity = 720896 (0.6875MB) used = 704680 (0.6720352172851562MB) free = 16216 (0.01546478271484375MB) 97.7505770596591% used To Space: capacity = 720896 (0.6875MB) used = 0 (0.0MB) free = 720896 (0.6875MB) 0.0% used PS Old Generation capacity = 47710208 (45.5MB) used = 589184 (0.5618896484375MB) free = 47121024 (44.9381103515625MB) 1.2349223042582418% used PS Perm Generation capacity = 16777216 (16.0MB) used = 5179648 (4.939697265625MB) free = 11597568 (11.060302734375MB) 30.87310791015625% used
发表评论
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Transfer
2017-06-29 23:03 0Find connections count: ... -
Discover the Mystery of Metaspace
2017-06-23 16:47 0The JDK 8 HotSpot JVM is now u ... -
Command Line JMX Client
2014-12-29 13:12 2567Command Line Parser: GNUComman ... -
Something about JVM class loading and initialization
2014-05-09 10:04 1000Class loading stages: Loadin ... -
When a class is loaded and initialized in JVM - Java
2014-05-08 19:09 953from: http://javarevisited.blo ... -
【深入Java虚拟机】之四:类加载机制
2014-05-08 15:12 865转载请注明出处:http://blog.csdn.net/n ... -
Java Reflection - Dynamic Class Loading and Reloading
2014-05-08 12:04 900From: http://tutorials.jenkov. ... -
Java 类加载与初始化
2014-02-19 19:12 777转载自:http://www.cnblogs.c ... -
javax.management.StandardMBean: When and Why. (Reposted)
2013-12-26 15:34 1049Q: When is a Standard MBean no ... -
JVM调优的"标准参数"的各种陷阱(转)
2013-11-11 19:55 1994From: http://hllvm.group.itey ... -
Java SE 6 HotSpot[tm] Virtual Machine Garbage Collection Tuning
2013-11-11 11:05 970(From: http://www.oracle.com/ ... -
An article about TLAB
2013-11-11 10:57 729(From: https://blogs.oracle.co ... -
【JVM】HotSpot JVM内存管理和GC策略总结(转)
2013-11-07 23:39 559JVM的相关知识是学习java高级特性必须要去深入学习的。平 ... -
jstat分析VM内存
2013-11-07 16:41 869Jstat 是JDK自带的一个轻量级小工具。全称“Java ... -
java的GridBagLayout网格包布局管理器使用详解 (转)
2013-11-01 16:44 0网格包布局管理是最复 ... -
java动态跟踪分析工具BTrace实现原理
2013-09-01 12:34 1232转自:http://kenwublog.com ... -
Java synchronize用法(转)
2012-11-05 00:20 1179在多个并发线程之间共用资源,就需要进行同步处理。Java虚拟机 ... -
Interview material collection
2012-07-09 23:05 11641. Why can't static methods be ... -
不要重复 DAO!(转)
2011-12-29 22:17 1211使用 Hibernate 和 Spri ... -
java中equals和==的区别(转)
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