Difference between Abstract class vs Interface in Java and When to use them

When to use interface and abstract class is one of the most popular object oriented design questions and almost always asked in Java, C# and...

Java Program to Find Sum of Digits in a Number using Recursion - Interview Question

Recently this question to asked was one of my reader, which inspired me to write this tutorial. There was usual check to solve this problem ...

10 Abstract Class and Interface Interview Questions Answers in Java

Abstract class and interface is very popular in any object oriented programming language or Java interview, and there are always one or more...

How to increment decrement date by days in Java - Tutorial example

While working in Java projects, we often needs to increment or decrement date e.g. adding one days to current date to get tomorrow's dat...

What is maximum Java Heap Size for 32 bit and 64-bit JVM - Frequently asked Questions

Maximum heap size   for 32 bit or 64 bit JVM looks easy to determine by looking at addressable memory space like 2^32 (4GB) for 32 bit JVM a...

How to Convert and Print Byte array to Hex String in Java

We often needs to convert byte arrays to Hex String in Java, In order to print byte array contents in readable format. Since many cryptograp...

How to check if two String are Anagram in Java - Program Example

Write a Java program to check if two String are anagram of each other, is another good coding question asked at fresher level Java Interview...

Can we Overload and Override Static methods in Java - Interview Question

Can static method be overridden in Java, or can you override and overload static method in Java , is a common Java interview question, mostl...

Top 15 Data Structures and Algorithm Interview Questions for Java programmer - Answers

Data structures and algorithm questions are important part of any programming job interview, be it a Java interview, C++ interview or any ot...

Difference between Struts 1 and Struts 2 framework

I had work previously on Struts 1 but never touched Struts 2, specially since Spring MVC was there to take the leading role. Recently one of...

Bitwise and BitShift Operators in Java - AND, OR, XOR, Signed Left and Right shift Operator Examples

Bitwise and Bit Shift operators in Java are powerful set of operators which allows you to manipulate bits on integral types like int, long, ...

Difference between Singleton Pattern vs Static Class in Java

Singleton pattern  vs   Static Class (a class, having all static methods) is another interesting questions, which I missed while blogging ab...

ReentrantLock Example in Java, Difference between synchronized vs ReentrantLock

ReentrantLock in Java is added on java.util.concurrent package in Java 1.5 along with other concurrent utilities like CountDownLatch , Execu...

How to create Immutable Class and Object in Java - Tutorial Example

Writing or creating immutable classes in Java is becoming popular day by day, because of concurrency and multithreading advantage provided b...

How to get Key from Value in Hashtable, HashMap or Map in Java

It's not easy to get key from value in Hashtable or HashMap, as compared to getting value from key, because Hash Map or Hashtable doe...

How to Swap Two Numbers without Temp or Third variable in Java - Interview Question

How to swap two numbers without using temp or third variable is common interview question not just on Java interviews but also on C and C++ ...

Top 5 Concurrent Collections from JDK 5 and 6 Java Programmer Should Know

Several new Collection classes are added in Java 5 and Java 6 specially concurrent alternatives of standard synchronized ArrayList , Hashtab...

How to Join Multiple Threads in Java - Thread Join Example

Join method from Thread class is an important method and used to impose order on execution of multiple Threads. Concept of joining multiple ...

What is Timer and TimerTask in Java – Tutorial Example

Timer in Java is a utility class which is used to schedule tasks for both one time and repeated execution. Timer is similar to alarm facili...

Difference between IdentityHashMap and HashMap in Java

IdentityHashMap in Java was added in Java 1.4 but still its one of those lessor known class in Java. Main difference between IdentityHashMap...