Question

What is exception propagation?

Give an example of a class that contains at least two methods, in which one method calls another. Ensure that the subordinate method will call a predefined Java method that can throw a checked exception. The subordinate method should not catch the exception. Explain how exception propagation will occur in your example.

Answer 1

Exception Propagation:- It is a process in which a method instead of handling checked exceptions itself, it transfers the exception to the caller of the method:-

Example of Exception Propagation in JAVA:-

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

public class ExceptionPropagation {

   public void method1() throws IOException { // here in this method instead of handling the exception itself, it is throwing the exception to the caller itself
       FileReader file = new FileReader("C:\\test.txt");
       BufferedReader fileInput = new BufferedReader(file);

       //print the contents of file
       while(fileInput.read() != -1) {
           System.out.print(fileInput.read());
       }

       fileInput.close();
   }

   public void method2() {
      
       //Exception should be handled while calling the method1() here
       try {
           method1();
       } catch (IOException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }
}