Exception chaining occurs when one exception causes another exception. The original exception is the cause of the second exception.
In Java, a chained exception is an exception that is caused by another exception. Chained exceptions are associated such that the previous exception causes each exception in the chain. It can help debug, as it can help us track down the root cause of an error.
We can use exception chaining in situations where another exception causes one exception. However, it's important to note that chaining can make our code more difficult to read and understand. Therefore, we should use exception chaining sparingly and only when necessary.
If we use chained exceptions, it is a good idea to document the chain in our code. It'll help others understand our code and make it easier to debug if an error occurs.
For example, if an InputStream throws an IOException, and the InputStream's read() method throws an EOFException, then the EOFException is the cause of the IOException. The following code demonstrates the use of chained exceptions:
import java.io.*;class ChainedExceptionDemo {public static void main(String[] args) throws IOException{try {throw new IOException("IOException encountered").initCause(new EOFException("root cause is EOFException"));} catch (Throwable e) {// Handle the IOExceptionSystem.out.println("Caught exception -> " + e);// Handle the EOFException hereEOFException eof = (EOFException) e.getCause();System.out.println("The cause is -> " + eof);}}}
In the above code, exception chaining allows us to handle both exceptions in a single catch block. If we want to access the original exception (the "cause"), we can use the getCause() method.
In this Answer, we learned about chained exceptions in Java, how they are useful for debugging, and how to create a chain of exceptions. We also learned how to access the original exception (the "cause") by calling the getCause() method on the exception.