write an exception java code example

Example 1: what is exception in java

In java exception is an object. Exceptions are created when an abnormal 
situations are arised in our program. Exceptions can be created by JVM or 
by our application code. All Exception classes are defined in java.lang. 
In otherwords we can say Exception as run time error.

Example 2: java throw an exception

public static void main(String[] args) {
	Scanner kb = new Scanner(System.in);
    System.out.println("Enter a number");
    try {
    	double nb1 = kb.nextDouble();
    	if(nb1<0)
        	throw new ArithmeticException();
        else System.out.println( "result : " + Math.sqrt(nb1) );
    } catch (ArithmeticException e) {
        System.out.println("You tried an impossible sqrt");
    }
}