Exception Handling in JAVA 4

Exception Handling in JAVA 4

Nested try statement

try statement can be nested inside another block of try. Nested try block is used when a part of a block may cause one error while entire block may cause another error. In case if inner try block does not have a catch handler for a particular exception then the outer try is checked for match.

class Excep
{
 public static void main(String[] args)
 {
  try
  {
   int arr[]={5,0,1,2};
   try
   {
    int x=arr[3]/arr[1];
   }
   catch(ArithmeticException ae)
   {
    System.out.println("divide by zero");
   }
   arr[4]=3;
  }
  catch(ArrayIndexOutOfBoundsException e)
  {
   System.out.println("array index out of bound exception");
  }
 }
}

Important points to Remember

1. If you do not explicitly use the try catch blocks in your program, java will provide a default exception handler, which will print the exception details on the terminal, whenever exception occurs.

2. Super class Throwable overrides toString() function, to display error message in form of string.

3. While using multiple catch block, always make sure that exception subclasses comes before any of their super classes. Else you will get compile time error.

4. In nested try catch, the inner try block, uses its own catch block as well as catch block of the outer try, if required.

5. Only the object of Throwable class or its subclasses can be thrown.