Exception Handling

• Exception handling is one of the powerful features of Java.
• Exception is also known as Runtime error
• Examples for some runtime errors are ClassNotFoundException, IOException, etc.
• Exception handling is the process of handling those exceptions that occur to maintain the normality of the program.
• java.lang.Throwable is the root class of Java exception.

Try and catch in Java

• The code that may have an exception is placed in try block
• The catch block catches the exception that is generated in the try block.

Types of Exceptions in Java

There are majorly 2 types of exceptions in Java

1. Checked

2. Unchecked

1. Checked Exception

The classes which directly inherit Throwable class except the RuntimeException and error.

Examples

IOException, SQLException, etc

2. Unchecked Exception

The classses which inherit RuntimeException class are unchecked exceptions.

Examples

ArithmeticException, NullPointerException etc

Examples

ArithmeticException

public class Example{  
  public static void main(String args[]){  
   try{  
      int b=5/0;//ArithmeticException  
   }
   catch(ArithmeticException e){
     System.out.println(e);
   }  
  }  
}  

Check output here

NullPointerException

Example 1

public class Example{  
  public static void main(String args[]){  
   try{  
      String name = null;  
      System.out.println(s.length());//NullPointerException
   }
  catch(NullPointerException e){
    System.out.println(e);
  }
  }  
}  

Check output here

Example 2

public class Example{  
  public static void main(String args[]){  
   try{  
       int a[]=new int[5];
       System.out.println(a[9]);
   }
   catch(ArrayIndexOutOfBoundsException e){
     System.out.println(e);
   }
  }
}

Check output here