Tip: Analyse impact on put and get method Case 1: - hashcode override - No   equals override - No What Will Happen- when you try to …

Singleton When there is only one instance creation is allowed OR We want to restrict instance creation of particular class and allow only one instanc…

Join is method from thread class. It can be called on thread object and when it is called, current thread will wait for other thread (on which join is ca…

CountDownLatch is utility under java.util.concurrent package. We initialise CountDownLatch with some integer count value. One or more threads will wa…

Sleep is method from Thread class. This can be called without object and will act on current running thread. Calling sleep on current thread will throw…

There are two ways you can create threads By extending Thread class from java.lang package By Implementing Runnable interface Lets explore these m…

Hi Readers, If you are beginner with Java then let me introduce your to constructor. Constructor class Animal() { public Animal ( ) { Sy…

Hi Readers We must have heard or someone just asked you about Coupling and Cohesion. So lets here it You must know Cohesion and Coupling for good unde…

Singleton Design Pattern In Software Engineering Singleton pattern restricts from creating more than one object of class.  Sometimes it's appr…

Hi Readers, Here I am writing few common ways to create new object in JAVA. Some ways are very frequent but some we rarely use, but it is good to know …

Access Modifiers In java we use access modifiers to control visibility of class and class members (Like instance variable, method, constructor) Jav…

Hi Readers, In this tutorial i am describing how ti integrate logger into your web application, spring project or java application. Log4j log4j is …

Why we need string buffer and string builder when we have string Hi Readers, If this question have struck your mind then i have answer for you. So t…

Hi Readers, Knowing about java keywords in java coding is very important. This comes under java for beginners. So we will cover two aspects of Java i…

Immutability in Java Readers, first we will see little about wrapper classes in Java. Many of us know that java is not all objects, there are som…

Enums in Java Enum type is a special data type. It allows user to create a variable which will have values from pre-defined constants. Enums are like …

In some languages char datatype is of 1 byte. So in those cases char is directly equivalent to byte. And you can confidently say that your char arr…

Static in Java I am describing how static is special and very useful in java - "static" is a keyword in Java. It has a special memor…

Both Abstract Class and Interface are used to implement abstraction in Java. But they are different in application and nature. Some key difference bet…

Checked Exception Are those which can be caught at compile time. Example - FileNotFound exception If some file that you are trying to read is not p…