What are Chained Exceptions?

One exception can be related to another using chained exceptions. We can use the chained exception mechanism in situations where we frequently need to throw a custom exception but want to retain the specifics of an original exception.

Constructors Of Throwable class Which support chained exceptions in java :

• Throwable(Throwable cause): Where cause is the exception that causes the current exception.
• Throwable(String msg, Throwable cause): where msg is the message for the current exception and cause is the exception that caused it.

Methods Of Throwable class Which support chained exceptions in java :

• getCause(): This method provides the precise cause of an exception.
• initCause(Throwable cause): method establishes the calling exception’s cause.

Example:

public class ExceptionHandling
{
	public static void main(String[] args)
	{
		try
		{
			// Creating an exception
			NumberFormatException ex =
					new NumberFormatException("Exception");

			// Setting a cause of the exception
			ex.initCause(new NullPointerException(
					"Coderzpy set the cause of the exception"));

			// Throwing an exception with cause.
			throw ex;
		}

		catch(NumberFormatException ex)
		{
			// displaying the exception
			System.out.println(ex);

			// Getting the actual cause of the exception
			System.out.println(ex.getCause());
		}
	}
}

Output:

java.lang.NumberFormatException: Exception
java.lang.NullPointerException: Coderzpy set the cause of the exception

Note: also read about the Interface vs Abstract class

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Rabecca Fatima

Staying up to the mark is what defines me. Hi all! I’m Rabecca Fatima a keen learner, great enthusiast, ready to take new challenges as stepping stones towards flying colors.