how to find memory leaks in java

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 memory exceptions An examp

Transferred from: http://www.linuxidc.com/Linux/2011-10/44785.htmbecause Android uses Java as a development language, and many people are using a problem that doesn't pay attention to memory. So sometimes encountered when the program runs constantly consumes memory, resulting in outofmemery, the program exits unexpectedly, which is caused by

more references to this bitmap.(vii) SUBSTRING's nightmare? ? public String substring (int beginindex, int endIndex) {? ? return new String (offset + beginindex,Endindex-beginindex,Value);? ?}? ? String (int offset, int count, Char value[]) {???this.value = value; ???this.offset = offset; ???This.count = count; ? ?}? ? That is, even if you just want to use some of these bytes, Java automatically saves the entire contents of the original string for yo

Phenomenon: Web unreachable, SSH Unable to login, desktop login verification failed. Login is normal after restarting the server. Cat/var/log/message shows that the root user has created more than 2000 sessions with insufficient memory. Enter the Tomcat installation directory (~/home/tomcat7_x/logs/) to view the log localhosts_time.log. The following error was found: 　　　　　java.lang.OutOfMemoryError:unable to create new native Threadat

Vector v = new vector (ten); 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 generate new objects, add them to the Vector object, and then empty the O reference. The problem is that when the O reference is empty,If a GC occurs,Can we create object objects that are recycled by GC?The answer is in the negative.Because, when the GC is tracking references in the code stack,Will fin

Handler Every beginner Android development is not open handler this "ridge", why it is a ridge, first of all, this is one of the essence of Android architecture, and then most people are aware of it but do not know why. Today, see Handler.post This method decided to go over the source code to comb the implementation of the handler mechanism. Update UI Asynchronously First of all, a must-back formula "main thread does not do time-consuming operations, child threads do not update the UI", this

);Cachedthreadpool.execute (T2);Cachedthreadpool.execute (T3);Cachedthreadpool.execute (T4);Cachedthreadpool.shutdown ();}}6.6 Threadpoolexecutorpublic class Testthreadpoolexecutor{public static void Main (string[] args){Create a thread pool from the constructorThreadpoolexecutor pool = new Threadpoolexecutor (2, 3, Timeunit.seconds, New linkedblockingqueueMyThread T1 = new MyThread ("T1");MyThread t2 = new MyThread ("T2");MyThread t3 = new MyThread ("T3");MyThread T4 = new MyThread ("T4");Pool.

Address: http://dev2dev.bea.com/pub/a/2005/06/memory_leaks.htmlEliminate memory leaks --Author: Staffan Larsen Summary Although Java Virtual Machine (JVM) and its garbage collector (Garbage Collector, GC) are responsible for managing most of the memory tasks, memory leakage

Http://www.360doc.com/content/060429/09/7469_107296.html SummaryAlthough Java Virtual Machine (JVM) and its garbage collector (Garbage Collector, GC) are responsible for managing most of the memory tasks, memory leakage may still occur in Java software programs. In fact, this is in a large project.Is a common problem.

because garbage collection suspends other work (may use multithreading or time slices, and it doesn't feel that way)2 speeds up the replication speed. Because the heap is internally flush to the remote, it is copied to direct memory (not heap memory) and then sent, while the outer heap memory is equivalent to omitting the work. Heap External

. Therefore, if a memory overflow is caused by an excessive number of threads, it can only be exchanged for more threads by reducing the maximum heap and the stack capacity of each thread, in the case of fewer threads.In addition, due to memory leaks in the Java heap, there is a brief explanation of the difference betw

OverviewThere 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.For developers engaged in C, C + + program development, in the field of memory management, they are the highest power of the emperor is t

Unveil Java memory management and java Memory ManagementPreface Compared with high-performance languages such as C and C ++, Java has the function that envy such programmers: Automatic Memory Management. It seems that

collector automatically collects the data that is no longer used. However, the disadvantage is that the access speed is slower due to the dynamic allocation of memory at run time. Thrown when heap memory is not expanded because it is fullJava.lang.OutOfMemoryError:Java Heap SpaceAbnormal. The workaround for this scenario is specific to Java tuning.in fact,

. the operating system allocates a limited amount of memory per process, the virtual machine provides parameters to control the Java heap and the method area of the two parts of the maximum memory, ignoring the program counter consumption of memory (very small), and the process itself consumes

is not expanded because it is fullJava.lang.OutOfMemoryError:Java Heap SpaceAbnormal. The workaround for this scenario is specific to Java tuning.in fact, Java memory is not limited to the above two types, but also:1. The program counter, (in the Thread PC register), records the line number of the bytecode executed by the current thread. 2. The local method stac

Deep Java core Java memory allocation principle explainingIntroduction: Stack, heap, Chang, although the same is the Java memory allocation operation area, but its scope of application and function is very different. This article will delve into the

Reference: http://oldblog.csdn.net/column/details/16384.html In "Fortress besieged" in a sentence, "people outside the wall want to go in, the wall inside people think out", use this to describe between Java and C + + This memory dynamic allocation and garbage collection technology surrounded by the "wall" is more appropriate. For developers engaged in C, C + +, in the area of

implement soft references if an object has soft references and enough memory space, the garbage collector does not recycle it. The memory of these objects is reclaimed only if there is insufficient memory space . The object can be used by the program as long as it is not reclaimed by the garbage collector. Soft references can be used to implement

time spent on pointer positioning (based on the pointer positioning of object instance data), and because object access is very frequent in Java, this overhead is a significant execution cost. For a hotspot, the second option is chosen.3. Common Oom and SOFOom is divided into two situations:memory Overflow (Overflow)Andmemory Leak (Leak)。OOM：OutOfMemoryError Exception,ThatMemory OverflowWhen the program is requesting