Oom?Java.lang.OutOfMemoryError:java head space heap memory overflowJava.lang.OutOfMemoryError:Permgen Space Java Eternal Overflow, that is, methods to overflow, generally because of the emergence of a large number of classes and JSPs, or the use of Cglib reflection mechanism,This can be resolved by changing the size of the method area and modifying it in the form of a similar-xx:permsize=64m-xx:maxpermsize=256m. In addition, too many constants, especially strings, can cause the method area to ov
This article describes some of the Zabbix monitoring JVM and Tomcat monitoring items Chinese interpretation, suitable for a certain basis for the people to see, for the Zabbix version of 2.4.4, memory recovery management mainly relies on the CMS and parnew mechanism. If there is a wrong place, please point out.Because the table can not be copied directly, here on
The JVM is the heavy load machine behind Java features and performance, which most developers take for granted. However, few of us understand how the JVM works-like task assignments and garbage collection, turning threads, opening and closing files, interrupting and/or JIT compiling Java bytecode, and so on.
Not being familiar with the
Reprint please be sure to indicate the source: Jiq Technical Blog-JiyichinIntroductionThis article focuses on some common virtual machine memory monitoring means, as well as the JVM runtime data area each part of the memory overflow occurrence and corresponding solution, overall, is a general summary, involving relatively not very deep, the purpose is to let oneself and other beginners have a framework, con
The individual believes that JVM tuning is primarily addressed by the following methods1. Set the appropriate maximum heap memory (maximum and value for Cenozoic and Laosheng generations) and minimum heap memory (the operating system memory size consumed by JVM startup), and set the scale allocation of the heap.2, set up the suitable new generation because of its impact on the system
Importnew Note: JVM performance Optimization series first 4 articles by importnew translation (first, second, third, fourth). This article was submitted by Sina Weibo: Wu Jie (@WildJay) to Importnew. Thanks Wu Jie! If you wish to share a good original article or translation, please submit it to importnew. Many programmers spend a lot of time tuning application-level pe
In addition to the integrated VISUALVM and Jconsole, the JVM also has small tools such as JPS, Jstack, Jmap, Jhat, Jstat, etc.Problems that may be encountered in development
OutOfMemoryError, Low memory
Memory leaks
Thread deadlock
Lock contention (lock contention)
The Java process consumes too much CPU
These problems may be overlooked by many people in their daily development (for example, some people encounter the probl
Many programmers spend a lot of time tuning application-level performance bottlenecks as they address JVM performance issues, and when you finish reading this series you will find that I might look at this kind of problem more systematically. I've said that the JVM's own technology limits the scalability of Java enterprise-class applications. First, let's start b
JVM Monitoring Tool Usage Guidance 2010-09-27 15:39 DOLPHIN-YGJ javaeye.comfont Size:T | T The use of the JVM monitoring tools can be found in time to remove the security risks, and here to describe the usage of several commonly used JVM
Many programmers spend a lot of time tuning application-level performance bottlenecks as they address JVM performance issues, and when you finish reading this series you will find that I might look at this kind of problem more systematically. I've said that the JVM's own technology limits the scalability of Java enterprise-class applications. First, let's start b
jvmstat_home:jvmstat installation directory JVMSTAT_JAVA_HOME:JDK directory, same as Java_home value
After configuring the two environment variables, you can run Jvmstat, run the command: Shell code VISUALGC PID #windows the system into the bat directory to run the command #linux the system into the bin directory after running the command
After the run interface automatically opens and displays the appropriate content, as shown in the figure:
From the jvmstat can be clearly observed in the
Many programmers spend a lot of time tuning application-level performance bottlenecks as they address JVM performance issues, and when you finish reading this series you will find that I might look at this kind of problem more systematically. I've said that the JVM's own technology limits the scalability of Java enterprise-class applications. First, let's start b
display performance statistics for the JVM, and the target virtual machine is marked with Vmid. virtualmachineidentifier (VMID) syntax: [protocol:][//]lvmid[@hostname [:p Ort][/servername] Protocol communication Protocol, if neither protocol nor hostname are specified, the optimal local protocol of the platform itself is used, and if the protocol is unspecified but hostname is specified, the default protoc
JVM monitoring tools-Introduction to several common toolsIntroduction to JVM monitoring tools
Jdk provides a powerful GUI-based jvm monitoring tool, which can be seen in the jdk bin directory, such as jconsole, jvisualvm, and orac
VISUALVM is a tool for performance tuning to monitor, display local, or remote server JVM work. With VISUALVM, we can monitor the various sub-pools of JVM memory, CPU, garbage collector, and so on, to discover potential leak points and configuration problems in program code.There are two ways to connect to the remote monitori
1, Jdb (the Java debuger)JDB is used to debug core files and running Java processes in real-time, with rich commands to help you debug, and its functionality is very similar to the DBX in Sun Studio, but JDB is specifically designed for Java applications.Now it should be said that the daily development of the jdb is seldom used, because now the IDE has been packaged for us, such as the use of Eclipse Invoke program is very convenient, as long as in very specific circumstances may use this comman
Performance monitoring tool: 1. Task Manager 2. Performance Logs and alarmsI. Task Manager1. Purpose: display applications running on the system Program Process, CPU, memory, and other usage and statistical information.2. Open Mode (local or remote)1> right-click the blank area in the taskbar and select "Task Manager"2> CTRL + ALT + del ctrl + ALT + end3> Ctrl +
different tiers, such as methods, classes, packages, or Java EE components. The CPU Views section includes:
Access Tree Call TreesDisplays an accumulated top-down tree that contains all the access queues that have been logged in the JVM. Both JDBC,JMS and Jndi service requests are commented on in the request tree. The request tree can be split according to the different needs of the servlet and JSP for the URL.
Hot spotsDisplays a list o
] is very usefulS0: Percentage of used space in vor space 0S1: Percentage of used space in vor space 1E: Percentage of space used in the Eden space areaO: Percentage of space used in the old space areaP: Percentage of space used in the perm space areaYgc: Number of young GC timesYgct: The time unit in seconds used by young GCFGC: number of full GC timesFgct: the unit of time in seconds for full GCGCT: Total time unit for garbage collection in seconds1.4Reduce the number of full GC times as much
functionA command-line tool for monitoring the various health status information for a virtual machine. It can display the class load, memory, garbage collection, JIT compiling and other running data in the process of local or remote virtual machine, on the server without GUI graphical interface and only provide plain text console environment, it will be the tool of choice for locating virtual machine performance
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