How to Throw Exceptions in Java?

[Bigga Lexx]

Hello folks,
I have recently started doing the coding in Java, so I don't have much idea about it. Now I started with the topic of an Exceptions. I just came to know that why we use an exceptions but I don't know how to throw it. Please tell me how to Throw Exceptions in Java? Please provide any coding so that I can easily understand.!!

[Deabelos]

Some code somewhere must throw before you can catch an exception. All the classes of an exceptions are derived from the Throwable class. You can also create your own exception classes to represent problems that can occur within the classes you write. Before catching an exception it is must to be thrown first. This means that there should be a code somewhere in the program that could catch the exception.

[kyosang]

For throwing an exceptions you did not have to work much. Actually throwing an exceptions is very simple to do. Since you are new you may find difficult but when you go on practicing you will find it very easy. You have to use throw statement to throw an exception or simply use the throw keyword with an object reference to throw an exception. Throwable objects are instances of any subclass of the Throwable class. The following is an example of the throw statement :

throw someThrowableObject;

[MindSpace]

You need a single argument for using the throw statement, which is a throwable object. As explained to you before the Throwable objects are instances of any subclass of the Throwable class. The following is the example of the same :

throw new VeryFastException();

You will have to keep in mind that the reference should be of type Throwable or one of its subclasses.

[absolute55]

I have provided you with a sample of the coding that may help you. The following is the sample for the same :

class ExceptionDemo extends Exception {
public ExceptionDemo(String msg){
super(msg);
}
}

public class Test {

static int  divide(int first,int second) throws ExceptionDemo{ 
  if(second==0) 
  throw new ExceptionDemo("can't be divided by zero");
return first/second;
 }

 public static void main(String[] args) {
  try {
System.out.println(divide(4,0));
  }
catch (ExceptionDemo excp) {
excp.printStackTrace();
  }
  }
}