throw error java

1public static void foo() throws IOException {
2    // some code here, when something goes wrong, you might do:
3    throw new IOException("error message");
4}
5
6public static void main(String[] args) {
7    try {
8        foo();
9    } catch (IOException e) {
10        System.out.println(e.getMessage());
11    }
12}

1public void doChangePin(int oldPin, int pin) throws Exception {	//need to add throws followed by exception name
2		if (oldPin == pinCode) {
3			pinCode = pin;
4		} else {
5			throw new Exception("some message");	//throwing the exception by creating its new object
6		}
7	}

1throw new java.lang.Error("this is very bad");
2throw new java.lang.RuntimeException("this is not quite as bad");

1public static void main(String[] args) {
2	Scanner kb = new Scanner(System.in);
3    System.out.println("Enter a number");
4    try {
5    	double nb1 = kb.nextDouble();
6    	if(nb1<0)
7        	throw new ArithmeticException();
8        else System.out.println( "result : " + Math.sqrt(nb1) );
9    } catch (ArithmeticException e) {
10        System.out.println("You tried an impossible sqrt");
11    }
12}

1Throws keyword used for handling exceptions. 
2  Where do you use it? Methods signature. 
3 If you want to handling right away in selenium or Api use “throws” keyword.
4Throw is creating an exception. Basically there are doing opposite. 
5Where do you use it? We use it with in the block.

1/* In this program we are checking the Student age
2 * if the student age<12 and weight <40 then our program 
3 * should return that the student is not eligible for registration.
4 */
5public class ThrowExample {
6   static void checkEligibilty(int stuage, int stuweight){ 
7      if(stuage<12 && stuweight<40) {
8         throw new ArithmeticException("Student is not eligible for registration"); 
9      }
10      else {
11         System.out.println("Student Entry is Valid!!"); 
12      }
13   } 
14
15   public static void main(String args[]){ 
16     System.out.println("Welcome to the Registration process!!");
17     checkEligibilty(10, 39); 
18     System.out.println("Have a nice day.."); 
19 } 
20}