What is the difference between Array and ArrayList is the quite common question for the Java interview and for the beginners who are learning Java programming. I have started writing the Java best practices series, this is one of the post for clearing the air on misconception about popular Java classes Array and ArrayList. 1. Flexible […]

If you are a Java programmer, then one of the common question comes into mind is How do I compile for compatibility with older versions of Java?. When you run your Java  program with an older version of the Java runtime environment, you may get the following Java exception if you have not compiled with the right version of […]

One of the basic Java interview question is what is the difference between abstract class and interface. If you are a beginner in Java, you can not avoid this question in any Java interview to test your knowledge on Java OOPs concepts. In this short tutorial I will write down the difference between abstract class […]

In this tutorial I am going to explain Java exceptions in details and how to use them in the real applications. One of the important measure to assess the quality of your Java code is to review the exception handling and how exceptions scenarios are handled. If you have to write an efficient exception handling, […]

Upcasting is assigning the sub class reference object to the parent class which is allowed in Java. Downcasting is assigning parent class reference object to the sub class which is not allowed in Java. However, if you do downcasting, there will not be any compiler error. But, there will be runtime exception java.lang.ClassCastException. Then why […]

Static Nested classes are inner classes which are declared inside another class and also declared with static keyword. The main difference between inner class and static nested classes is that inner classes are non-static and static nested classes are static. Also known as static classes. Static nested classes can be accessed using the enclosing class […]

This example show the order of the Java initialization blocks. Java has static initializer, instance initializer and constructor for initializing the variables. These blocks are used for the different purposes and leads to confusion among the programmers. Order of the execution of these blocks are as follows: All Static Initializers executed in the same order […]

In my previous example I have explained how to use static initializer in Java.This example shows how to use the instance initializer block in Java. The following are the few features of instance blocks. Instance initializers are block of code with out any keyword keyword. The code which needs to be initialized will be put […]

This example shows how to use the static initializer in Java. The following are the few features of static blocks. Static initializers are block of code with static keyword. These are executed when the class is loaded or accessed first time by any application. Only static variables can be initialized inside static blocks. Instance variables […]