🔹 What is a Lambda Expression?
A Lambda Expression in Java is a short block of code that takes in parameters and returns a value, used primarily to implement functional interfaces.
✅ Think of it as a way to write anonymous functions more cleanly.
📌 Syntax of Lambda
Examples:
🎯 Functional Interface Reminder
A Functional Interface has only one abstract method.
Example:
You can use a lambda to implement it:
✅ Real-World Usage
🔹 1. Using Lambda with Threads
🔹 2. Using Lambda with Collections
🔹 3. Comparator Example
📦 Common Functional Interfaces in java.util.function
| Interface | Method Signature | Example Usage |
|---|---|---|
Predicate<T> |
boolean test(T t) |
Filtering lists |
Function<T,R> |
R apply(T t) |
Mapping values |
Consumer<T> |
void accept(T t) |
Printing, logging |
Supplier<T> |
T get() |
Supplying default values |
- More concise and readable code
- Enables functional programming
- Reduces boilerplate (e.g., anonymous inner classes)
- Great for stream and collection APIs
🧠 Summary
| Concept | Example |
|---|---|
| Basic Syntax | (a, b) -> a + b |
| Functional Interface | One method interface (e.g., Runnable) |
| Use Case | Collections, threads, event handling |
| Advantage | Concise, elegant, modern code |