In Object-oriented programming, one object is related to other to use functionality and service provided by that object. This relationship between two object is known as association in  object orien

This post is another addition in best practices series available in this blog. In this post, I am covering some well-known and some little known practices which you must consider while handling ex

Why wait, notify and notifyAll is declared in Object Class instead of Thread is famous core java interview question which is asked during all levels of Java interview ranging from 2 years, 4years to q

A semaphore is a counter that protects the access to one or more shared resources. In this tutorial, we will learn how to use the binary semaphore for controlling access to a shared resource by mu

It's been almost a month Java 8 is released and I am sure all of you are exploring new features of JDK 8. But, before you completely delve into Java 8, it’s time to revisit some of the cool features

In this post, I will write a piece of code which will create a deadlock situation and then i will discuss that way to resolve this scenario.In my previous post, i written about Auto reload

Java 8 release is just a couple of weeks away, scheduled at 18th March 2014, and there is lot of buzz and excitement about this path breaking release in Java community. One of feature, which is syno

Difference between String, Stringbuffer and StringBuilderString is one of the most important classes in Java and anyone who starts with Java programming uses String to print something on console by

Converting a byte array to String seems easy but what is difficult is, doing it correctly. Many programmers make mistake of ignoring character encoding whenever bytes are converted into a String or

We all know the basic statement that finalize() method is called by garbage collector thread before reclaiming the memory allocated to the object. In this post, we will drill down more deeply into t

What is a tricky question? Well, tricky Java interview questions are those questions which has some surprise element on it. If you try to answer a tricky question with common sense, you will most like

Java ClassLoader loads a java class file into java virtual machine. It is as simple as that. It is not a huge complicated concept to learn and every java developer must know about the java class loade

The Fork/Join library introduced in Java 7 extends the existing Java concurrency package with support for hardware parallelism, a key feature of multicore systems. In this Java Tip Madalin Ilie demons

tough core Java interview questions and answersWhat is tough core java interview question ? Why do people look for tough Java questions before going for interview? well I don't thing I need to answe

Wait vs sleep in JavaDifferences between wait and sleep method in Java Thread is one of the very old question asked in Java interviews. Though both wait and sleep puts thread on waiting state, they

Java Generics TutorialGenerics in Java is one of important feature added in Java 5 along with Enum, autoboxing and varargs , to provide compile time type-safety. Generics is also considered to be on

Java 8 now allows you to add non-abstract method implementations to interfaces by utilizing the default and static keyword. Methods with default keyword are known as default methods or defender meth

The following post is a comprehensive summary of the developer-facing changes coming in Java 8. As of March 18, 2014, Java 8 is now generally available.I used preview builds of IntelliJ for my I

Gadzooks, time flies!  Been too long since I blogged…  no time for something deep so here’s another quicky brain dump.Azul Systems has been running HotSpot with a Tiered Compilation system since 200

An overview of memory saving techniques in Javaby Mikhail VorontsovThis article will give you the general advices on memory consumption optimization in Java.Memory usage optimization is

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ContentsThreading ArchitectureThe Reactor PatternComponent ArchitectureAcceptorDispatcherDispatcher-Level EventHandlerApplication-Level EventHandlerConclusionResourcesIf you are asked to w

Read more http://tutorials.jenkov.com/java-nio/index.html

What are the benefits of knowing how garbage collection (GC) works in Java? Satisfying the intellectual curiosity as a software engineer would be a valid cause, but also, understanding how GC works

This is the fifth article in the series of "Become a Java GC Expert". In the first issue Understanding Java Garbage Collection we have learned about the processes for different GC algorithms, about

1. 首先String不属于8种基本数据类型，String是一个对象。 　　因为对象的默认值是null，所以String的默认值也是null；但它又是一种特殊的对象，有其它对象没有的一些特性。 　　2. new String()和new String(“”)都是申明一个新的空字符串，是空串不是null； 　　3. String str=”kvill”； String s

By jonthecollector on Feb 01, 2008I drew this diagram on a white board for some customers recently. They seemed to like it (or were just being very polite) so I thought I redraw it for your amusemen

通过分析这两个关键字的分析，我们可以理解java中锁的概念。一个是实例锁（锁在某一个实例对象上，如果该类是单例，那么该锁也具有全局锁的概念），一个是全局锁（该锁针对的是类，无论实例多少个对象，那么线程都共享该锁）。实例锁对应的就是synchronized关键字，而类锁（全局锁）对应的就是static synchronized（或者是锁在该类的class或者classloader对象上）。

Java 中一共有 4 种类型的引用 : StrongReference、 SoftReference、 WeakReference 以及 PhantomReference (传说中的幽灵引用 呵呵), 这 4 种类型的引用与 GC 有着密切的关系,  让我们逐一来看它们的定义和使用场景 :   1. Strong Reference        StrongReference

整个教程中已经不时的出现一些内存管理和垃圾回收的相关知识。这里进行一个小小的总结。Java是在JVM所虚拟出的内存环境中运行的。内存分为栈(stack)和堆(heap)两部分。我们将分别考察这两个区域。 栈栈的基本概念参考纸上谈兵: 栈 (stack)。许多语言利用栈数据结构来记录函数调用的次序和相关变量(参考Linux从程序到进程)。在Java中，

一个运行时的Java虚拟机实例的天职是：负责运行一个java程序。当启动一个Java程序时，一个虚拟机实例也就诞生了。当该程序关闭退出，这个虚拟机实例也就随之消亡。如果同一台计算机上同时运行三个Java程序，将得到三个Java虚拟机实例。每个Java程序都运行于它自己的Java虚拟机实例中。　　Java虚拟机实例通过调用某个初始类的main()方法来运行一个Java程序。而这个main()

How do you find middle element of LinkedList in one pass is a programming question often asked to Java and non Java programmers in telephonic Interview. This question is similar to checking palindro

OverviewThe expected behaviour for volatile fields is that they should behave in a multi-threaded application the same as they do in a single threaded application.  They are not forbidden to behav

Table of ContentsThe Internal Java Memory ModelHardware Memory ArchitectureBridging The Gap Between The Java Memory Model And The Hardware Memory ArchitectureVisibility of Shared ObjectsRa

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This article will give you an overview of some popular Java data types memory consumption. This article follows An overview of memory saving techniques in Java article earlier published in this blog

On this post, we are going to talk about the dangers of using optimistic read-locks, namely, how sensitive they are to the invariants.One noticeable example of an optimistic read-lock, is the St

This article will describe how String.intern method was implemented in Java 6 and what changes were made in it in Java 7 and Java 8.First of all I want to thank Yannis Bres for inspiring me to

19 July 2014: article text cleanup, added a chapter on JDK to Trove migration.16 July 2012: original version.This article would describe Trove library, which contains a set of primitive coll

What is the difference between HashMap, LinkedHashMap and TreeMap in Java? I don't see any difference in the output as all the three has keySet and values. What are Hashtables?Map m1 = new HashM