Exceptions in Java

Exception is a run-time error which arises during the execution of java program. The term exception in java stands for an exceptional event.

Exceptions in Java

Exception is a run-time error which arises during the execution of java program. The term exception in java stands for an exceptional event.

Exceptions in Java

Exceptions in Java

     

Introduction

Exception is a run-time error which arises during the execution of  java program. The  term exception in java stands  for an exceptional event. It can be defined as abnormal event that  arises during the execution and  normal flow of  program. The exceptional event can also be error in the program. 

Error in Java are of two type-

1.Compile-time Error-Compile -time Error are those error which occurs when you don't follow the Syntax of the code or do wrong in writing a code of the Programming language. The Compiler detect the Syntax  error in the code of the Programming language during its execution. For example in normal java coding ,you need your every statement to be terminated with semicolon(;).if you don't follow the rule, this will give you Compile-time error.

2.Run -time Error-Run-time error are the error which arises during the execution of a program. For example. The program runs out of the memory, result in Run-time error.

Why  Exceptions Occur-

An Exception is Run-time error that arises during the normal execution of Java program. In case of Run-time error, if you divide a number by zero or unable to open a file which does not exist, an exception is raised. In java exception are handled by Run-time System or user-defined code. A run-time error throws an exception.

Error handling plays a important role while developing an application. Following are the situation in which run-time error arises-

  1. Search a file which does not exist.
  2. Dividing a number by zero.
  3. Allocating Memory error.
  4. Problem in accessing Network Connectivity.

What is Exception Class-

Object Class is the base class of the exception hierarchy.. Object class is the super class of Throwable class.Throwable class is the super class of all the exceptional class and error class. In java you can throw exception Object which are derived from throwable class. The following Syntax for declaring a throwable class .

Throwable()

The Syntax represent a constructor of throwable class with no arguments.

In the same way we can declare a constructor of Throwable class with a userdefined Parameter.

Throwable(String Parameter)

Parameter can be message that may be userdefined included in Throwable class.

Exceptional Class-

  1. ClassNot Found Exception- Exception arises when a class is being reffered,but no such definition of class name is being found.
  2. Runtime Exception- handles the Exception arises during the runtime execution of the program.
  3. Illegal Access Exception-This Exception is thrown when method is not found.

Exceptional Hierarchy

Exception Hierarchy

Built in Exception-

The built-in exception in java are of following types classified on the basis of exception handled by the java compiler.

1.Checked Exception-These exception are the objects of the Exception class and its subclasses. It don't include the Run time Exception. These exception occurs due to invalid user input, problem in the network connectivity database connection). This also arises when we forget to import the packages. For Example java.sql.sqlexception,java.io.ioexception.The Exception problem can be overcome by implementing Try-Catch block which u see in Example in exception.

2.Unchecked Exception-These exception are the run-time errors that arises due to incorrect arguments passed to the public method written by the programmer. The Compiler never checks the Unchecked exception during the program compilation. For example, Dividing any number by zero is an unchecked exception.

Tutorials

  1. Java Exception - Handle Exceptions in Java
  2. Exceptions in Java
  3. Exceptional Example in Java
  4. Number Format Exception
  5. Null Pointer Exception
  6. Index Out of Bound Exception
  7. Example to show exception in java
  8. Example to show exception handling in java
  9. Example to show class exception in java
  10. Example to show Argument Exception in java
  11. Example to compile a java file with the help of the program
  12. Constructor Exception in Java
  13. Example to show ArraylistException in Java
  14. Example to show cast exception in java
  15. Example to show clone exception in java
  16. Example to show Collection exception in java
  17. List of Java Exception
  18. User Defined Exception
  19. Example to create exception object in java
  20. Example to show Array exception in java
  21. Example to show ArrayoutofboundException in java
  22. Example to show Hash map exception in java
  23. Example to show Hash table exception in java
  24. Example to show Iterator exception in java
  25. User Defined Exception
  26. Java Illegal State Exception
  27. Unhandled Exception
  28. Java Assertion
  29. Serializable Exception
  30. Java Parse int Exception
  31. List of Java Exception
  32. Java Exception Thread
  33. Simple Date Format Exception
  34. Example to create Interface in java
  35. Example to show double exception in java
  36. Example to show Enumeration exception in java
  37. Example to show Finally exception in java
  38. Integer exception in java
  39. Exception handling in java
  40. Finally in java