Exception Chaining in Java: Example, Cause and Practice

Problem summary

Catch a low-level exception and wrap it in a higher-level exception.

Starter code

// Create DataProcessingException
// Wrap NumberFormatException as cause

public class Main {
    public static void main(String[] args) {
        String data = "not a number"; // Test case 1
        
        // Process data, chain exceptions
    }
}

Expected output and test cases

• Chained exception

  Processing failed: Data parsing error
  Cause: For input string: "not a number"

• Valid data

  Processing succeeded: 42

• Null input

  Processing failed: Data parsing error
  Cause: null

Hints

1. new HighLevelException(message, cause)
2. getCause() retrieves wrapped exception
3. Preserves stack trace information

How to approach the problem

Catch the low-level exception and pass it as the cause when constructing the higher-level exception. Call getCause() when diagnostic code needs to inspect the original failure.

Common mistakes

• Creating a new exception without passing the original cause.
• Printing only the wrapper message and discarding the original stack trace.
• Using exception chaining for normal control flow instead of genuine failures.

Related Exception Handling exercises

• Practice Custom Exception Class in Java
• Practice Input Validation with Exceptions in Java
• Practice Retry with Exceptions in Java

Practice all Exception Handling exercises · Run this idea in the Java compiler