Labels

.NET Job Questions About Java Absract class Abstract class Abstract Class and Interface Aggregation ajax aop apache ofbiz Apache ofbiz tutrial Association authentication autocad basics batch Binary Tree bootstrap loader in java build Builder design pattern C++ Job Questions caching CallableStatement in java certifications Chain of responsibility Design pattern charts check parentheses in a string Classes classloader in java classloading concept code quality collage level java program Composition concurrency Concurrency Tutorial Converting InputStream to String Core Java core java concept core java interview questions Core Java Interview Questions Core Java Questions core java tutorial CyclicBarrier in Java data structures database Database Job Questions datetime in c# DB Db2 SQL Replication deserialization in java Design Patterns designpatterns Downloads dtd Eclipse ejb example/sample code exception handling in core java file handling injava File I/O vs Memory-Mapped Filter first program in spring flex Garbage Collection Generics concept in java grails groovy and grails Guice Heap hibernate Hibernate Interview Questions how-to IBM DB2 IBM DB2 Tutorial ide immutable Interceptor Interface interview Interview Questions for Advanced JAVA investment bank j2ee java JAVA Code Examples Java 7 java changes java class loading JAVA Classes and Objects Java Classloader concept Java classloading concept java cloning concept java collection Java collection interview questions Java Collections java concurrency Java CountDownLatch java definiton Java design pattern Java EE 5 Java EE 6 Java Exceptions Java file Java Garbage Collection Java generics Java Glossary java hot concept java immutable concept Java Interface Java interview Question java interview question 2012 java interview question answer Java Interview Questions Java Interview Questions and Answers java interview topic java investment bank Java Job Questions java multithreading java multithreading concept java new features Java Packages java proxy object java questions Java Serialization Java serialization concept java serialization interview question java session concept java string Java Swings Questions java synchronization java threading Java Threads Questions java tutorial java util; java collections; java questions java volatile java volatile interview question Java Wrapper Classes java.java1.5 java.lang.ClassCastException JavaNotes javascript JAX-WS jdbc JDBC JDBC Database connection jdk 1.5 features JDK 1.5 new features Concurrent HashMap JMS interview question JMS tutorial job JSESSIONID concept JSESSIONID interview Question JSF jsp JSP Interview Question JSP taglib JSTL with JSP Junit Junit Concept Junit interview question.Best Practices to write JUnit test cases in Java JVM Linux - Unix tutorial Marker Interfaces MD5 encryption and decryption messaging MNC software java interview question musix NCR java interview question Networking Job Questions news Object Serialization Objects ojdbc14.jar OOP Oracle Oracle SQL Query for two timestamp difference orm own JavaScript function call in Apache ofbiz Packages Palm Apps patterns pdf persistence Portal Portlet Spring Integration Prime number test in java programs Rails Reboot remote computers REST Ruby Sample application schema SCJP security Senior java developer interviews servlet3 servlets session tracking singleton design pattern Spring Spring 2.5 Framework spring ebook Spring framework concept spring MVC spring pdf Spring Security Spring Security interview questions SQL SQL performance SQL Query to create xml file Sql Query tuning ssis and ssrs StAX and XML string concept string immutable string in java strings struts Struts2 Struts2 integration synchronization works in java Technical Interview testing tips Tomcat top Tutorial Volatile in deep Volatile working concept web Web Developer Job Questions web services weblogic Weblogic Application Server websphere what is JSESSIONID xml XML parsing in java XML with Java xslt


Tuesday, 16 July 2013

Java 5: New features in Concurrency

Most of the new features in concurrency are implemented in the java.util.concurrent packages. There are also new concurrent data structures in the Java Collections Framework:
  • Lock objects support locking idioms that simplify many concurrent applications.
  • Executors define a high-level API for launching and managing threads. Executor implementations provided by java.util.concurrent provide thread pool management suitable for large-scale applications.
  • Concurrent collections make it easier to manage large collections of data, and can greatly reduce the need for synchronization.
  • Atomic variables have features that minimize synchronization and help avoid memory consistency errors.
LOCK OBJECTS
Lock objects work very much like the implicit locks (monitors) used by synchronized code. As with implicit locks, only one thread can own a Lock object at a time. Lock objects also support a wait/notify mechanism, through their associated Condition objects. All the lock objects are defined in the java.util.concurrent.lock package. The biggest advantage of Lock objects over implicit locks is their ability to back out of an attempt to acquire a lock. The tryLock method backs out if the lock is not available immediately or before a timeout expires (if specified). The lockInterruptibly method backs out if another thread sends an interrupt before the lock is acquired.

EXECUTORS
The java.util.concurrent package defines three executor interfaces:
  • Executor: A simple interface that supports launching new tasks.
  • ExecutorService: A sub-interface of Executor, which adds features that help manage the lifecycle, both of the individual tasks and of the executor itself.
  • ScheduledExecutorService: A sub-interface of ExecutorService, supports future and/or periodic execution of tasks.
CONCURRENT COLLECTIONS
The java.util.concurrent package includes a number of additions to the Java Collections Framework.
  • BlockingQueue defines a first-in-first-out data structure that blocks or times out when you attempt to add to a full queue, or retrieve from an empty queue.
  • ConcurrentMap is a subinterface of java.util.Map that defines useful atomic operations. These operations remove or replace a key-value pair only if the key is present, or add a key-value pair only if the key is absent. The standard general-purpose implementation of ConcurrentMap is ConcurrentHashMap, which is a concurrent analog of HashMap.
  • ConcurrentNavigableMap is a subinterface of ConcurrentMap that supports approximate matches. The standard general-purpose implementation of ConcurrentNavigableMap is ConcurrentSkipListMap, which is a concurrent analog of TreeMap.
ATOMIC VARIABLES
The java.util.concurrent.atomic package defines classes that support atomic operations on single variables (ex. AtomicInteger). All classes have get and set methods that work like reads and writes on volatile variables. The atomic compareAndSet method also has these memory consistency features, as do the simple atomic arithmetic methods that apply to integer atomic variables.

References

No comments:

Post a Comment

LinkWithin

Related Posts Plugin for WordPress, Blogger...