Search results
Results From The WOW.Com Content Network
Since JDK 1.2, Java has included a standard set of collection classes, the Java collections framework Doug Lea , who also participated in the Java collections framework implementation, developed a concurrency package , comprising several concurrency primitives and a large battery of collection-related classes. [ 19 ]
It is possible for any Java code to use for other purposes the compareAndSet() method on various concurrent classes to achieve Lock-free or even Wait-free concurrency, which provides finite latency. Lock-free techniques are simple in many common cases and with some simple collections like stacks.
Collection implementations in pre-JDK 1.2 versions of the Java platform included few data structure classes, but did not contain a collections framework. [4] The standard methods for grouping Java objects were via the array, the Vector, and the Hashtable classes, which unfortunately were not easy to extend, and did not implement a standard member interface.
In the following piece of Java code, the Java keyword synchronized makes the method thread-safe: class Counter { private int i = 0 ; public synchronized void inc () { i ++ ; } } In the C programming language , each thread has its own stack.
In concurrent programming, a monitor is a synchronization construct that prevents threads from concurrently accessing a shared object's state and allows them to wait for the state to change. They provide a mechanism for threads to temporarily give up exclusive access in order to wait for some condition to be met, before regaining exclusive ...
Such languages provide synchronization constructs whose behavior is defined by a parallel execution model. A concurrent programming language is defined as one which uses the concept of simultaneously executing processes or threads of execution as a means of structuring a program.
Concurrent data structures are significantly more difficult to design and to verify as being correct than their sequential counterparts. The primary source of this additional difficulty is concurrency, exacerbated by the fact that threads must be thought of as being completely asynchronous: they are subject to operating system preemption, page faults, interrupts, and so on.
The class is dangerous in a multithreading scenario because both methods can be called simultaneously, so the value of val (which is not atomic—it's updated in multiple steps) could be undefined—a classic race condition. You can, of course, use synchronization to solve this problem, which in this trivial case is easy.