Guided: Records and Pattern Matching in Java SE Apps

Table of Contents

1. Challenge

   Step 1: Getting Started

   Welcome to Records and Pattern Matching in Java SE Apps. This lab modernizes a notification processing application using modern Java features: records, sealed interfaces, and pattern matching.

   The starter code contains traditional Java classes with verbose boilerplate. By the end, the code will be concise, type-safe, and expressive. > This lab experience was developed by the Pluralsight team using Forge, an internally developed AI tool utilizing Gemini technology. All sections were verified by human experts for accuracy prior to publication. For issue reporting, please contact us.

2. Challenge

   Step 2: Converting Classes to Records

   Java Records provide a compact syntax for immutable data classes. A record automatically generates:

   • A canonical constructor
   • Accessor methods (e.g., recipient() instead of getRecipient())
   • equals(), hashCode(), and toString() methods

   This step converts all three notification classes to records.

3. Challenge

   Step 3: Creating a Sealed Type Hierarchy

   Sealed interfaces restrict which classes can implement them. This creates a closed type hierarchy that the compiler can reason about.

   With a sealed interface, the compiler knows all possible implementations, enabling exhaustive pattern matching without a default case.

4. Challenge

   Step 4: Pattern Matching with Switch

   Pattern matching for switch allows switching directly on object types. Combined with sealed interfaces, it provides:

   • Type-safe handling of all cases
   • Concise, readable code
   • Compiler-verified exhaustiveness

   This step replaces the verbose if-else chain with an elegant switch expression.

5. Challenge

   Step 5: See It in Action

   The refactoring is complete. The notification service now uses:

   • Records for concise, immutable data classes
   • Sealed interfaces for a closed type hierarchy
   • Pattern matching for elegant, type-safe processing

   Run the demo to see the modernized code in action. Congratulations — you've finished the lab! By completing these steps you modernized a notification service using three powerful Java features: records, sealed interfaces, and pattern matching. These changes eliminated boilerplate code, enabled compile-time type safety, and replaced verbose if-else chains with concise switch expressions.