It's all about Java

NullPointerException causes and reasons Since Java is object oriented programming language, every thing is considered to be an object. and there is always a scope of an object to be null or "No value".  Since Java supports primitive data types, Java is not considered to be pure Java object oriented programming language.   Few Notable points about NullPointerException NullPointerExceptions is unchecked exception Please read post  Exception handling and java keywords before reading this article Usually if program tries to fetch the value from reference and finds nothing as value, then program throws NullPointerException 'Zero' is not null And empty String is not considered to be null It is not the subclass of RuntimeException class Demo code that throws NullPointerException  package com.allabtjava.blog; public class DemoNullPointerException { class BeanDemo { String name; Integer ID; public String getName() { return name; } public void s...

First of all, please read below blog post to understand basics of Exception Handling in java. Exception handling and java keywords To continue from there, Basically Java default API has hierarchy of  java classes to support different uses cases of exceptions.  The parent class of all Exceptions and Errors is Throwable . Please check below pictorial representation of  API Hierarchy. Exception: The class Exception and any subclasses that are also not subclasses of RuntimeException are checked exceptions. And all subclasses of RuntimeException and RuntimeException class itself are Unchecked exception . Rest all are Checked exceptions Examples of Unchecked Exceptions:            ArrayIndexOutOfBoundException          NullPointerException Error: An Error is a subclass of Throwable that indicates serious problems that a reasonable application should not try to catch. Most such errors are abnormal conditions. Examples: T...

Exception: Exception in a programming language and in English language is pretty similar. Exception means being different from or not following the rules. And in programming language like Java, exception is  an event which occurs during the execution of a program that disturbs the complete flow of application or program. When something beyond expected happens while executing a program is considered as an error. handling these errors or abnormality is called as Exception handling. Exception Handling: Exception handling in java is managed with the help of java keywords and java API support..              1. Java Keywords             2. Java API support Java Keywords:   There are 5 keywords in Java.           1. Try           2. catch           3. finally           4. throw    and 5. throws These five keywor...