monitor jvm memory

multithreading, and languages that support multithreading on multithreaded platforms should provide a solution to the problem. The JVM is a virtual computer, it will also face multi-threaded concurrency problems, Java programs run on the Java Virtual Machine platform, Java programmers can not directly control the underlying thread to register cache memory synchronization between, then Java from the syntact

I stitched up a JVM memory graph from online search: as shown in:Let's consider a few questions:How does the 1.jVM work?How is the 2.JVM runtime memory allocated?3. In what area do we write Java code (classes, objects, methods, constants, variables, etc.) in the end?VM Run-t

Deep understanding of JVM memory zone and memory overflow Document directory 1.2. HotSpot Virtual Machine 1.3. troubleshooting of OOM exceptions 1.4. Reference Java memory overflow exception Data Area During Running Program counters Row number indicator of the bytecode executed by the current thread

Summary: After Tomcat deploys multiple projects, the startup Tomcat is normal and the error occurs when you access the projectCheck on the internet and tried several times, only to solve, the solution is recorded to facilitate later viewing or to meet the same problem friends have a referencePermGen space is what will not say, looking for a lot of online, feel there is no need to remember these conceptsThe root of the problem is that the JVM does not

Tomcat itself cannot run directly on the computer, it needs to rely on a hardware-based operating system and a Java virtual machine. Tomcat's memory overflow is essentially a JVM memory overflow, so at the beginning of this article, the Java JVM's memory-related knowledge should be described in detail.First, Java

Tomcat itself cannot run directly on the computer, it needs to rely on a hardware-based operating system and a Java virtual machine. Tomcat's memory overflow is essentially a JVM memory overflow, so at the beginning of this article, the Java JVM's memory-related knowledge should be described in detail.First, Java

Tomcat itself cannot run directly on the computer, it needs to rely on a hardware-based operating system and a Java virtual machine. Tomcat's memory overflow is essentially a JVM memory overflow, so at the beginning of this article, the Java JVM's memory-related knowledge should be described in detail.First, Java

lot of implementations, even if you have a deep understanding of the Java Virtual Machine specification and interested in it, you can write a Java virtual machine, of course, the difficulty is not difficult to imagine.Structure diagramIt is a structure diagram of a JVM that is quoted in the Baidu Library, because the run-time pool is the area allocated by the method area, so the constant pool is not running in this graph.Memory Area DetailedFor the a

are advantages to both ways, and the biggest benefit of the Bureau and access method is that the reference is stored in a stable handle address, when the object is moved, only the instance data pointer in the handle is changed, and the reference itself does not need to be modified. The greatest advantage of pointer access is the speed, which saves the overhead of a pointer-to-location, and because object access is very frequent in Java, once such overhead is a very significant cost.Specific acc

Source: http://blog.csdn.net/yu422560654/article/details/7952613Heap Heap Memory understandingA JVM instance has only one heap of memory, and the size of the heap memory can be adjusted. After the class loader reads the class file, it needs to put the class files, methods, constants into the heap

value and-xx:maxpermsize must be greater than 25.6M ===================================Ultimately, it depends on the exact configuration of your machine.Please refer to the following article in the configuration barThere is a Eclipse.ini file under the Eclipse folderxms128m-xmx512m-xx:permsize=64m-xx:maxpermsize=128m Here are a few questions: 1. What are the meanings of each parameter? 2. Why do some machines I set-xmx and-xx:maxpermsize to 512M after eclipse can be started, and some machines w

Tomcat itself cannot run directly on the computer, it needs to rely on a hardware-based operating system and a Java virtual machine. Tomcat's memory overflow is essentially a JVM memory overflow, so at the beginning of this article, the Java JVM's memory-related knowledge should be described in detail.First, Java

] 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

after understanding the memory management, I believe you will have a deep understanding. Memory Partitioning When it comes to memory, it is a data storage area only when the program is running, and for this area, each virtual machine has its own way of partitioning, but they all have to conform to the Java Virtual machine's basic specifications. In the virtua

JVM Memory ManagementI. Physical memory and virtual memory1. Physical memory(1) RAMThe so-called physical memory is what we usually call RAM (random memory ).(2) registersIn a computer, there is also a storage unit called register

operating system, the default kernel space and user space ratio is 1:1 (that is, 2GB kernel space, 2GB user space), and the default ratio of 32-bit Linux system is 1:3 (1GB kernel space, 3GB user space). third, which components in Java need to use memory1. Java HeapThe Java heap is the area of memory used to store Java objects, and the heap size is applied to the operating system once the JVM is started,-x

Jackson triggered the String. intern () bug, resulting in a continuous increase in memory, JVM-Java Memory leakage, I can use Jackson locally to reproduce this problem. import java.io.IOException; import java.util.Map; import java.util.Random; import com.fasterxml.jackson.core.JsonFactory; import com.fasterxml.jackson.core.type.TypeReference; import com.fasterxml

When reading this article, at least first of all, the concept of the JVM, working principle, structure composition, have certain basic understanding, the nonsense does not say much, this article is straight to the point, directly to work more common concepts: class, Class object, instance object, static method, Non-static method, static attribute, non-static attribute, etc. directly into the use and allocation of