free java memory profiler

LockLocks are the simplest way to do concurrency, and the cost is the highest, Java Before JDK1.5 is guaranteed by the Synchronized keyword to ensure that synchronization, he is an exclusive lock, using synchronized synchronization lock for thread blocking and wake-up switching and user-state kernel state switching operation additional waste of CPU resources, locks there are other shortcomings, when a thread is waiting for the lock, It can't do anythi

gain thread can access an object, the object is eligible for garbage collection. (Question five: How does the garbage collector work?) If the garbage collector finds that an object cannot be accessed by any live thread, he will consider the object to be eligible for deletion, add it to the recycle queue, but not destroy the object immediately, and when to destroy and free memory is unpredictable. Garbage c

://techfoxbbs.com/data/ Attachment/forum/201504/07/155225wuurh1utbr8jlhjj.png "Width="/>Heap: The Java heap (Java heap) is the largest piece of memory managed by a Java virtual machine. The Java heap is an area of memory that is s

1. Core idea of garbage collection algorithm The Java language establishes a garbage collection mechanism for tracking objects that are in use and for discovering and reclaiming objects that are no longer in use (references). This mechanism can effectively guard against the two risks that may occur in dynamic memory allocation: the memory exhaustion caused by exc

First, what is the Java memory modelThe Java Virtual Machine specification attempts to define a Java memory model (MODEL,JMM) that masks the access differences of various hardware and operating systems to allow Java programs to ac

object3, the allocation of memory into the pointer collision and the free list of two ways, allocating memory also to ensure concurrency security, there are two ways.Pointer collision: As long as the free space in heap memory is very regular, use and unused space is all con

itself by the JVM, containing the required memory for the method area, internal processing of the JVM, or optimization (such as Jitcompiler,just-in-time Compiler, the immediately compiled code cache), Code for each class structure, such as running a constant pool, fields, and method data, and methods and construction methods.The JVM memory contains the following sections: Heap

*/publicclasstwodimensionalarraydemo{publicstaticvoidmain ( String[]args) {/** declares a two-dimensional array of type string classroom* the length of the first dimension is 2 and the length of the second dimension is 3* A one-dimensional array of length 2, each of which is a one-dimensional array of length 3 */string[][]classroom=newstring[2][3];classroom[0] [0]= "1th row 1th column";classroom[0][1]= "1th row 2nd Column";classroom[0][2]= "1th row 3rd column"; classroom[1 ][0]= "2nd row 1th co

continues to trace, it finds that the memory space pointed to by the V reference has a reference to the object. This means that although the O reference is already empty, there are still other references to object objects that can be accessed, so the GC cannot release it. If after this loop the object object has no effect on the program, we assume that the Java program has a

method area, internal processing of the JVM, or optimization (such as Jitcompiler,just-in-time Compiler, the immediately compiled code cache), Code for each class structure, such as running a constant pool, fields, and method data, and methods and construction methods.The JVM memory contains the following sections: Heap Memory: Storing Java objects