java threadlocal

,synchronized's wider function range (synchronization mechanism).3.synchronizedSynchronized keyword is the use of the lock mechanism of Java automatic implementation, there are generally synchronous method and synchronous code block two ways. All objects in Java automatically contain a single lock (also known as a monitor), and when any of its synchronized methods are called on an object, the object is lock

things to note when using this threadlocal:If you define a number of thread variables, you may not be able to create the thread's exception, because some Web server for threads will define the thread pool, when using threadlocal to create a lot of threads, processing time is relatively long, then these threads will not be released, the result will cause the stack overflow, The program is not responding. At this point you need to be aware that the cur

make the code redundant.You can use variables of type threadlocal to solve this problem. First generate a transaction ID in the controller or any preprocessor interceptor, then set the transaction ID in Threadlocal, and finally, whatever method the controller calls, it can get the transaction ID from threadlocal. And the controller of this application can handle

thread, and then the value of the variable is set to the Threadlocalmap object, of course, if the Threadlocalmap object obtained is empty, is created by using the Createmap method.// returns the Threadlocals property of the thread object directly threadlocalmap Getmap (Thread t) { return t.threadlocals;}The thread object has an attribute threadlocals of type Threadlocalmap, which is dedicated to saving all of its thread-local variables. This property is null when the thread object is initia

first meaning here)8 Else9 Createmap (t, value);Ten}Note here that there is a map in threadlocal, but this map is not the map we normally use, but Threadlocalmap,threadlocalmap is an internal class of threadlocal that is not used externally. When Threadlocal is used, the first is to get to the current thread object, and then get to the current thread loc

error code is written to the corresponding errno of this thread. The system call in the code is a fake system call, Some_system_call ().In the actual development, for the developer, he actually does not see Set_errno (), Get_errno () These functions, he only need to take errno on the line.650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M01/6F/6D/wKiom1Wbudzhz-3IAAUruAEgEOY812.jpg "title=" Selection _ 007.png "alt=" Wkiom1wbudzhz-3iaauruaegeoy812.jpg "/>Java's

Analysis of Java threadlocal usage The definition of ThreadLocal in the JAVA API documentation is: This class provides thread-local variables. These are variables differ from their normal counterparts in so each thread that accesses one (via it get or set method) ha s its own, independently initialized copy of the va

advantage. So if the use of jdk1.2,jdk1.3 and so on, do not imagine the Sparrow to become Phoenix ... Then look at the nature of threadlocal and synchronized. The former does not care about the space, but can not bear to wait, the latter is indifferent to waiting, but just do not like to waste space. This also reflects a rule of the algorithm: usually use the scene to determine the ratio of time and space, both time-saving and provincial algorithms

(); }2. Possible problems: Memory leaks Note: Because ThreadLocal.ThreadLocalMap.Entry inherits from a weak connection, the next GC can release the memory of the key name Threadlocal object when the strong connection is broken. However, value: Strong connection used in ThreadLocal.ThreadLocalMap.Entry, cannot be automatically gc by program, must trigger GC through remove, set, GET, etc./*** The entries in this hash map extend WeakReference, using * I