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COMPUTER SOFTWARE APPLICATION - CITS

Java throw Exception
In Java, exceptions allow us to write good quality codes where the errors are checked at the compile time instead
of runtime and we can create custom exceptions making the code recovery and debugging easier.

Java throw keyword
The Java throw keyword is used to throw an exception explicitly.

We specify the exception object which is to be thrown. The Exception has some message with it that provides the
error description. These exceptions may be related to user inputs, server, etc.

We can throw either checked or unchecked exceptions in Java by throw keyword. It is mainly used to throw a
custom exception. We will discuss custom exceptions later in this section.

We can also define our own set of conditions and throw an exception explicitly using throw keyword. For example,
we can throw ArithmeticException if we divide a number by another number. Here, we just need to set the
condition and throw exception using throw keyword.
The syntax of the Java throw keyword is given below.

throw Instance i.e.,

1 throw new exception_class(“error message”);
Let’s see the example of throw IOException.

1 throw new IOException(“sorry device error”);
Where the Instance must be of type Throwable or subclass of Throwable. For example, Exception is the sub class
of Throwable and the user-defined exceptions usually extend the Exception class.
Java throw keyword Example

Example 1: Throwing Unchecked Exception
In this example, we have created a method named validate() that accepts an integer as a parameter. If the age is
less than 18, we are throwing the ArithmeticException otherwise print a message welcome to vote.

TestThrow1.java
In this example, we have created the validate method that takes integer value as a parameter. If the age is less
than 18, we are throwing the ArithmeticException otherwise print a message welcome to vote.
public class TestThrow1 {
//function to check if person is eligible to vote or not
public static void validate(int age) {

if(age<18) {
//throw Arithmetic exception if not eligible to vote
throw new ArithmeticException(“Person is not eligible to vote”);
}
else {
System.out.println(“Person is eligible to vote!!”);

}
}
//main method
public static void main(String args[]){

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