monitor jvm memory

Introduction What is the ultimate algorithm? In fact, the current JVM uses the algorithm, is not really the ultimate. Maybe a few years later, there will be a new ultimate algorithm, and almost certainly, because LZ believe in the ability of people. So what does a generational collection algorithm do with GC? Object classification As has been said in the previous chapter, the generational collection algorithm is based on the different characteris

Web services are always inexplicably run after a period of time after the JVM directly outofmemory error, memory leak problem is not easy to find, this article on some of the basic knowledge to find memory leaks to do a summary, does not involve a specific case analysis. 1 data display of JVM

The compilation and execution of a Java program is as follows:. java--compiles the-->. Class ClassLoader is responsible for loading individual bytecode files (. class) after loading. class, executed by the execution engine, which requires the runtime data area to provide data during execution According to the JVM specification, JVM memory is divided into five pa

cannot be reordered, so the processor does not reorder it when it encounters a memory barrier-protected instruction. The knowledge points about where to add memory barriers, what kinds of memory barriers, and what they do, are not explained here. You can refer to the JVM specification for relevant data.Here's a look a

This article provides a detailed analysis of the JVM memory limit of 2 GB in Linux, for more information, see the 32-bit JVM we usually use (64-bit JVM will lose 10-20% performance, which is generally not recommended ), the addressing space of 32-bit programs should be 4 GB. Why does the

of the memory will be recycled, a portion of the surviving memory will be copied to the survivor from zone, and after multiple collections, if the From zone memory is also allocated, then a memory recycle will occur and the remaining objects will be copied to the to area. When the to area is full, a

1. JVM class loading mechanismThe entire life cycle of a class from being loaded to the memory of the virtual machine to unloading it is: loading, connecting (validating, preparing, parsing), initializing, using, and unloading phases.Load: Find the corresponding class file according to the search path, then pour.Check: Check the correctness of the class file to be loaded.Prepare: Allocates storage space for

Parse Java object reference and JVM Automatic Memory Management-Linux general technology-Linux programming and kernel information. The following is a detailed description. The application design interface for Object Reference is defined in JDKTM1.2. The application design interface allows the application to interact with the JVM

. Environmental Preparation and DescriptionWin7Jdk1.6.0_31Tomcat6Linux CentOSLocal VISUALVM to connect to the remote JVM, the configuration needs to be made, and VISUALVM is mainly remotely connected through JMX and jstatd two ways.JMX connections can look at System information, CPU usage, how many timelines the thread is on, manually perform garbage collection, and more at the system-level level.The jstatd connection method provides

Original address: http://blog.csdn.net/kingofworld/article/details/17718587First, JVM memory model overall architecture diagramRun-time Data areaThe JVM defines different run-time data areas, which are used to execute the application. Some regions start and destroy with the JVM, and some of the data in some areas is th

JVM memory model and memory error Java Virtual machine managed memory will contain several runtime data regions: Program counter, method area, stack area, heap area, local method stack. (1) The program counter is a smaller memory space, which can be regarded as the line num

The method of adjusting eclipse memory on the internet indicates that the JVM parameters can be set in the Eclipse.ini file. But running the program still found that the memory has not changed, not the set of 1024M, but still 107M (the default program in Eclipse JVM configuration is:-xms8m-xmx128m).The reason for the e

Reference: "Java Virtual machine explaining"I. Overview of the memory distribution inside the JVM virtual machinewhere the method area I'm on the blog Java Virtual machine class loading process memory situation underlying source code analysis and ClassLoader explanation explained in detail, can refer to that article. It is mainly stored in: Run constant-time pool

Reference articles:1.Java Cenozoic, old age, lasting generation and meta space2.Java Memory and garbage collection tuning3. The class information of the method area, also known as the permanent generation, belongs to the Java heap. The heap in Java is the largest chunk of memory that the JVM manages, and is primarily used to hold instance objects for various clas

JVM size default is 64m, if you want to increase the memory of the program run, if you want to resize the JVM, you can configure the parameters of the VM in the Run configuration,-xmx100m that the size of the configuration is 100M.The following is a description of some configurations.-vmargs-xms128m-xmx512m-xx:permsize=64m-xx:maxpermsize=128mThe-vmargs descriptio

JVM memory Composition The JVM stack consists of the heap, stack, local method stack, and method zone. The structure is shown as follows: 1) Heap The memory of all objects created through new is allocated in the heap, and their size can be controlled through-xmx and-XMS. The heap is divided into the new generation and

Label: blog HTTP Io ar use Java SP strong on In the previous section, we introduced the JVM garbage collection principles. There are also several garbage collection algorithms: tag-clearing algorithm, replication algorithm, tag sorting algorithm, and generational collection algorithm; now we will talk about the hotspt garbage collector. This section will be just a theory. Java Virtual Machine specifications have no specific provisi

8192K,8% used [0x331d0000, 0X33287FC0, 0x339d0000) from Space 1024K,0% used [0x339d0000, 0x339d0000, 0x33ad0000) to space 1024K,0% used [0x33ad0000, 0x33ad0000, 0x33bd0000) tenured generation total 10240K, used 4096K [0x33bd0000, 0x345d0000, 0x345d0000) The space 10240K,40% used [0x33bd0000, 0x33fd0010, 0x33fd0200, 0x345d0000) Compacting Perm gen Total 12288K, used 145K [0x345d0000, 0x351d0000, 0x385d0000) The space 12288K,1% used [0x345d0000, 0x345f4468, 0x345f4600, 0x351d0000) Ro space 10240K

cenozoic ( Two survivor have 20%, generally speaking, the Cenozoic recovery of the variable accounted for 98%, only 2% of the variables need to replicate the reservation, of course, when the survivor space is insufficient, need to rely on other memory, generally used in some areas of the old age distribution guarantee (Handle promotion )) What is a shared guarantee. Before the minor GC, the JVM first che

There is a "high wall" between Java and C + + that is surrounded by dynamic memory allocations and garbage collection techniques, and people outside the walls want to go in, but the people inside the wall want to come out. --in-depth understanding of Java Virtual machines: JVM advanced features and best practicesThe Java Virtual machine divides the memory it mana