jvm profiler

JVM garbage collection and jvm garbage collection JVM garbage collection This article attempts to briefly introduce the mainstream JVM garbage collection mechanism. Scope of a garbage collection Discussion JVM memory is divided into several parts: Method Area,

Talking about JVM and memory allocation, talking about JVM Memory Allocation 1. program memory allocation Initial Memory Allocation When a program is ready to run, it first needs memory from the Java virtual machine, but the Java Virtual Machine itself does not have the permission. It can only apply for memory from the operating system. At this time, the Java Virtual Machine will have an initial memory, He

Jvm-related parameters, tuning, and jvm parameter tuning Common jvm parameters are as follows: -Xmx1024m: Set the JVM maximum available memory to 1024 MB.-Xms1024m: Set JVM to enable the memory to be 1024 MB. This value can be set to the same as-Xmx to avoid

The implementation of bytecode commands in jvm is important, and the implementation of bytecode in jvm is important. Java is interpreted and executed, including the dynamic link feature, which provides a lot of space for flexible expansion during parsing or running. How to compile and parse the inheritance, encapsulation, and polymorphism features of object-oriented languages in

JVM-Garbage Collector, jvm-garbage collection This article mainly introduces several JVM garbage collectors. As shown below, the three above are the new generation collectors, The following three are the collectors of the old generation. The G1 collector can be used for the collection of the new generation and the old generation.

JVM tuning series: garbage collection and jvm Tuning Summary: jvm is a required series, which summarizes some common jvm collection mechanisms for easy reference. Before optimization, we must understand how it runs. java's Garbage Collection is usually called "GC", which was born in The Lisp Language of MIT in 1960,

Chapter 4 JVM garbage collection algorithm and Chapter 4 jvm garbage collection Note: Before reading this article, you need to know how to determine whether the object is alive or not. For details, see Chapter 3 JVM memory recycle area + object survival judgment + reference type + garbage collection thread. Note: This article mainly refers to the distributed Java

Chapter 9 JVM tuning recommendations and chapter 9 JVM tuning recommendations Note: This article mainly references distributed Java applications: basics and practices 1. JVM optimization is mainly about memory optimization, mainly in two aspects: Size of each generation Garbage Collector Selection 2. Size of each generation Common Adjustment Parameters

Solve JVM memory overflow and jvm memory overflow Today I encountered a problem. When I restarted Tomcat 6 when adding the configuration file (*. xml) content, the console reported the error: java. lang. StackOverflowError; That is, stack overflow error. Memory overflow occurs when the memory used by the program is larger than the maximum memory provided by the virtual machine. Memory overflow depends on

Jvm supports Simple testing of the maximum number of threads and jvm supports the maximum number of threads. Recently, to test the maximum number of concurrent threads in Openfire, a large number of threads are required to simulate the client. I am always confused about the number of threads that a JVM instance can open. Therefore, I plan to test the number of th

Learn JVM easily (II)-memory model, visibility, Command Re-sorting, jvm Model In the previous article, we introduced the basic running process and memory structure of JVM, and had a preliminary understanding of JVM, in this article, we will explore the visibility of variables in java based on the

Chapter 6 JVM garbage collector (2) jvm garbage collection The previous chapter records several common garbage collectors. For details, see chapter 5 JVM garbage collector (1). 1. G1 Note: From the Perspective, compared with CMS, G1 is different only in the final "filter and recycle" section (CMS is a concurrent cleanup). In fact, the overall heap memory divi

Million threads per JVM and million threads per jvm I. environment requirements:1.64bit Linux2.64bit JDK3. Memory is large enough, 512 GB4. cpu: 64 processorsII. Test Tool: [DieLikeADog. java]Java-server-Xmx6G-Xms6G-Xmn600M-Xss228K-XX: PermSize = 50 M-XX: MaxPermSize = 50 M-XX: + DisableExplicitGC DieLikeADogIII. Check Configuration:1. ps-Lf 2. ulimit-a =>>>> Mainly view the value of-n and-u.3. cat/proc/sys

JVM tuning-New Generation and jvm tuning New Generation A new generation of Java virtual machines, including eden space and two dedicated vor spaces. The new generation is used to store newly created objects. The new generation features fast object updates and produces a large number of "Dead objects" in a short time ". Garbage collection for young generations is called secondary garbage collection (minor

In this section we summarize the memory allocation policy in the JVM. The directory is as follows: Memory allocation policyObject first in New Generation Eden AssignmentLarge objects go straight into the old ageLong-lived objects will enter the old age.Dynamic Object Age DeterminationSpace allocation guaranteed memory allocation policyThe automatic memory management advocated in the Java technology system can be attributed to two parts: allocating mem

Difference between heap memory and stack memory in JVM, and between jvm heap memory Java divides memory into two types: stack memory and stack memory. TheSome basic types of variables and Object Reference variables are allocated in the function stack memory.. When a variable is defined in a code block, java allocates memory space for the variable in the stack. When the scope of the variable is exceeded, jav

JVM learning-runtime data zone and jvm learning data Zone Unlike C and C ++ programs, the memory management of Java programs is taken over by the java Virtual Machine (JVM), which reduces the burden on Java programmers, however, if an OutOfMemory or StackOverFlow Exception error occurs, it is difficult to locate the error quickly if you do not know the memory man

GC mechanism: Allocating an object using the new keyword; when releasing an object, the program cannot access the object again, as long as it is assigned NULL to all references to the object, and we call the object "unreachable." The GC is responsible for reclaiming the memory space of all "unreachable" objects. JVM Tuning Method: 1. The most basic advice is to release the references to unwanted objects as soon as possible. Most programmers use tempor

Jvm learning notes 1 (garbage collection algorithm) and jvm learning notes I. Reasons for the garbage collection mechanism In java, when no object reference points to the memory originally allocated to an object, the memory becomes garbage. A jvm system-level thread Automatically releases the memory block. Garbage collection means that the object no longer needed

Memory, as an important resource in the system, plays a key role in the stable operation and efficient operation of the system, unlike languages like Java and C, which do not require the developer to allocate memory and reclaim memory, but rather the JVM manages the allocation of object memory and the collection of object memory (also known as garbage Collection, GC). This greatly reduces the difficulty of writing the program for developers, but one s