java memory profiler

on the characteristics of the processor (multi-level cache system, multi-core processor, etc.), so that the machine instruction is more consistent with the performance of the CPU and maximizes the machineSpecial Memory operationsVolatile modified variables: visibility; Disable command reordering optimizationFinal field: The final field value can be seen in the other thread once it is initialized in the constructorSpecial rules for long and double var

Atitit. Improved stability ----- Analysis of Memory leakage PermGen OOM and solutions... java, permgen... java Atitit. Improved stability ----- Analysis of Memory leakage PermGen OOM and solutions... java 1. Division of memory ar

A memory leak means that an object or variable that is no longer being used by a program is occupied in memory. Java has a garbage collection mechanism that ensures that an object is no longer referenced, that is, when an object becomes orphaned, and the object is automatically purged from memory by the garbage collect

Run-time data regionThe Java Virtual machine divides the memory it manages into several different data regions during the execution of a Java program. These areas have their own uses, as well as the creation and destruction of time, and some areas exist as the virtual machine process starts, and some areas are built and destroyed depending on the start and end of

Jni,java Native Interface is the programming interface for Native code. JNI enables Java code programs to interact with native code-call native code in a Java program, and embed Java virtual machines in native code to invoke Java.JNI programming is widely used in software development, and its advantages can be summed u

Java handles large files, generally with bufferedreader,bufferedinputstream such as buffered IO classes, but if the file is oversized, the faster way is to use Mappedbytebuffer.Mappedbytebuffer is a File memory mapping scheme introduced by Java NIO, which is very high in read and write performance. The main thing about NIO is the implementation of support for asy

Deep understanding of Java Virtual Machine Reading Notes (2) Creation of HotSpot Java objects, memory layout and access methods, javahotspot In-Memory Object creation, object structure, and access method.I. Object Creation At the language level, object creation is just a new Keyword. What is the process in a virtual ma

Deep understanding of Java Virtual Machine-Chapter 6 Java Memory Model and thread, and Chapter 4 Chapter 2 Java Memory Model and thread Java Memory Model Master

A brief description of the memory area of Java: Run-time data region Hotspot Virtual Machine Object I. Overviewsecond, run-time data area2.1 Program CountersProgram Counter Register, which represents the line number indicator of the byte code executed by the current thread, the PC in the operating system, both of which are a concept. Execution is done by changing this counter to select the

1. Program Counter: is a small memory space that can be viewed as a line number indicator executed by the current thread, and the byte code parser, when working, selects the next byte-code instruction that needs to be executed by the value of the variable program counter. The basic functions of a program's branch-loop jump, exception handling, and thread recovery are all dependent program counters. Java Vi

Suppose a thread assigns a value to a variable: variable = 3;The memory model needs to fix a problem: "Under what conditions, the thread reading variable will see this value as 3?" ”This may seem natural, but if there is a lack of synchronization, there are many factors that make it impossible for a thread to see the results of another thread immediately or forever.Such as:1. The order of instructions generated in the compiler can be different from th

Transformation and memory allocation in Java inheritance, and transformation and allocation in java inheritance When reading a book, a piece of code can be messy. The code is like this: Package inheritance; abstract class People {public String tag = "Crazy Java handout"; // ① public String name = "Parent"; String getNa

much, the body collapsed. I still have a blood pill. Stay with me a lot. I remember, I will be grateful. The biggest is home and loved ones.Tell us: Health first, the capital of revolution. It's easy to say, it's hard to do. (try to be regular, whether you stay up late) And keep optimistic, it's good for your body. Moderate amount of exercise Some details to note and try: Bubble foot .... Two. TextI want to combine my own story and say it's really sad. But I'm not care

Java memory overflow and java Overflow 1. java Heap Overflow JAVA heap is used to store object instances. As long as you constantly create objects and ensure that GC Roots directly have accessible paths to objects, so that the garbage collection mechanism does not know the o

Record a Java Memory Leak analysis and a java leakCurrent Environment Code address Git address: https://github.com/jasonGeng88/java-network-programmingBackground Not long ago, a new project was launched. This project is a stress testing system, which can be viewed as a replaying Vocabulary (http request data) and conti

Turn from: 39048737Configure XMS, XMX, PermSize, MaxPermSize in the Tomcat server memory sizeTurn from: 52938043A Java Virtual machine memory configuration:(1) Operation: project name (e.g. CK02) right-click (select option Properties)->run/debug settings-> Select the program you want to execute (for example: Launch), tap (edit. ), select (x) =arguments under VM a

The so-called memory leak refers to an object or variable that is not being used by the program has been occupied in memory. There is a garbage collection mechanism in Java that ensures that an object is no longer referenced when the object is programmed to orphan, and the object is automatically erased from memory by

In-depth understanding of Java Virtual Machine (2) Creation of Hot Spot Java objects, memory layout and access methods In-Memory Object creation, object structure, and access method.I. Object Creation At the language level, object creation is just a new Keyword. What is the process in a virtual machine? (1) determine w

New Object ();Main reference: "In-depth understanding of Java Virtual Machine", without the consent of the author and the original book to prohibit reprint.Data regions in the JVMThe data in the JVM is divided into the following areas:which1. Program Counter:A program counter is a small amount of memory space that is the line number indicator of the bytecode that is executed by the current thread . In other

Previous blog "Dead java Concurrency"-in-depth analysis of the volatile implementation principle has described the characteristics of volatile: volatile visibility; For a volatile read, you can always see the final write of this variable; volatile atomicity; volatile is atomic for a single read/write (32-bit long, Double), except for composite operations, such as i++; A "memory barrier" is