java memory leak detection tools

One, the problem arisesProject AdoptionTomcat6.0 for server, the database ismysql5.1, the database persistence layer ishibernate3.0, tospringMVC3.0 for Frames, after the completion of project development, on the eve of the stability of the machine, the test data is inserted4 article/S, update4 article/S, Access300 plays/S, smooth running speed, and it starts running slowly after three days., the number of visits reached1500W Times to throwjava heap space ends Two 1. Pre-analysis for connectio

A few days ago wrote a memory leak of the article, which describes the memory leaks related knowledge: http://blog.csdn.net/u010590685/article/details/46973735But the example given here is not very good, see a good example here today to add to everyone.If we write a stack ourselves, here is the Pop method: publicpop(){ Object object=arrays[size];

1. Static collection classes like HashMap, vectors, etc. are most prone to memory leaks, and the lifetime of these static variables is consistent with the application, and all object objects cannot be freed, as they will always be used by vectors and so on.Static vector v = new vector (); for (int i = 1; i　　In this example, there is a reference to the vector object in the code stack with reference to the V and object o. In the For loop, we constantly

A memory leak is an object or variable that is no longer being used and is always occupied in memory. However, there is a garbage collection mechanism in Java that can automatically purge objects that are no longer in use from memory.Even so, there is a case of memory leaks

string can be said to be one of the most common Java types, but I've recently heard JDK6 inside String.substring There is a memory leak bug, gang stunned! Let's see what the situation is. This is the code that can cause the exception in thread "main" Java.lang.OutOfMemoryError:Java Heap space: publicclasstestgc{privatestringlargestring= Newstring (newbyte[100000

Write NIO programs often use Bytebuffer to read or write data, then use bytebuffer.allocate (capability) or bytebuffer.alloctedirect (capability) To allocate the cache? The first is to allocate JVM heap memory, which belongs to the GC jurisdiction, which is relatively slow due to the need for copying, and the second is to allocate OS local memory, which is not in GC jurisdiction, and is relatively fast beca

I. Memory leaks due to expired referencesNote: When the object is not used, the object is set to NULL, and this time the virtual machine does not necessarily release the memory, as to when the release is determined by the garbage collection algorithm.When an object is not in use, it does not reclaim the possibility of a memory

, so its life cycle is synchronized with the person, and the class object corresponding to the person class is resident in memory in case the person class is not unloaded until the program finishes running. -As a result, the object objects referenced by obj, once created, will also reside in memory until the end of the run. -4: Release references to useless objects as early as possible the5: Avoid creating

Yes. The reason Java causes memory leaks is clear: a long lifecycle object holds a reference to a short lifecycle object and is likely to have a memory leak, although the short lifecycle object is no longer needed, but because the long lifecycle object holds its reference and cannot be reclaimed, this is the scenario w

(); }} class Mymemory{public MyMemory () {}///The objects are stored in Heap public void Heapleaktest () {list4. Test ResultsHeap OverflowException in thread "main" Java.lang.OutOfMemoryError:Java heap spaceAt Com.dangdang.memoryleak$mymemory.heapleaktest (memoryleak.java:27)At Com.dangdang.MemoryLeak.main (memoryleak.java:12)Stack OverflowException in thread "main" Java.lang.StackOverflowErrorAt Com.dangdang.memoryleak$mymemory.stackleaktest (memoryleak.java:34)At Com.dangdan

Original address: http://www.javatang.comA period of time on-line after the system upgrade, there is a serious high CPU problem, so began a series of optimization processing, now the process into a series of articles.Basic conceptsWhen analyzing a Java memory leak, you need a dump file that records the memory footprint

process that uses it exits.In Linux, each file has 2 counters, I_count and I_nlink. I_count indicates the number of files being invoked. I_nlink represents the number of hard links. The jmap Command jmap command can be used to output all in-memory objects, and can even dump the heap in the VM into text as binary. You can output details of all objects in the memory of a specified

Package com.ckw.mianshi;/** * Test memory leaks * Several events in Java that cause memory leaks: * A reference to an object that is held in a container such as 1.hashmap,verctor, although the object is already set to NULL, a memory leak * 2 will still occur. The use of the

.... ..... ....... ..............................Snapshot resolved.Started HTTP server on port 7000Server is ready. Dump file created Thu Mar 16:45:06 CST 2015 Snapshot Read, resolving ... Resolving 264282 objects ... Chasing references, expect, dots ..... ..... ..... ....... ......................... Eliminating duplicate references .... ..... ....... .............................. Snapshot resolved. Started HTTP server on port 7000 Server is ready. 3. The address bar input ip

Override hashcode member variable changed, object in set cannot find1. Use the Hashcode function of the object to determine the memory location initially, and if there is no storage object at that location, store the object in this2, if the hash function directly calculated memory address space already has an object exists, will use the object's equals to determine whether the object is equal, if not equal

. Enter the function for one-step execution.The step out function allows the code pointed to by the current arrow to run the program Function return.Run to cursor enables the program to run to the code indicated by the cursor.1.5 view the use of the toolThe most important thing in the debugging process is to observe the state of the program during running so that we can find out Program errors. The state here includes the value of each variable, the value in storage, and the value in

This article mainly introduces the introduction and usage of two Python memory detection tools, which can be used to analyze the memory usage of Python programs. If you need a friend, refer to when I wrote a program last year, if you are not sure about your memory usage, you

Memory leaks are always a headache, and the following three commands I personally find quite useful. 1. Jstack (unique under Linux) You can observe the current status of all threads in the JVM and the current state of the thread Jstack 2083 The output reads as follows: 2, Jmap (Linux is unique, but also a very common command) Observe the footprint of the running JVM's physical memory. The parameters are

When I wrote a program myself last year, I was unsure of my memory usage and wanted to find a writing tool to print the memory usage of a program or function.Here is a record of the basic usage of the last 2 memory detection tools found, as well as the need for future analys

When I wrote a program last year, I was not sure about my memory usage. I wanted to find a write tool to print the memory usage of the program or function.Here, we will record the basic usage of the two memory detection tools we found last time. It is also necessary to analy