throw exceptions in java code example

Example 1: throw io exception java

public static void foo() throws IOException {
    // some code here, when something goes wrong, you might do:
    throw new IOException("error message");
}

public static void main(String[] args) {
    try {
        foo();
    } catch (IOException e) {
        System.out.println(e.getMessage());
    }
}

Example 2: java how to throw exception

public class ThrowException{
  public static void main(String [] args) throws Exception{ 
    //throws Exception line is needed if not using try-catch block
    throw new Exception("Errmessage");
  }
}

Example 3: throwing exceptions java

/* In this program we are checking the Student age
 * if the student age<12 and weight <40 then our program 
 * should return that the student is not eligible for registration.
 */
public class ThrowExample {
   static void checkEligibilty(int stuage, int stuweight){ 
      if(stuage<12 && stuweight<40) {
         throw new ArithmeticException("Student is not eligible for registration"); 
      }
      else {
         System.out.println("Student Entry is Valid!!"); 
      }
   } 

   public static void main(String args[]){ 
     System.out.println("Welcome to the Registration process!!");
     checkEligibilty(10, 39); 
     System.out.println("Have a nice day.."); 
 } 
}

Example 4: throw and throws keyword in java

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