feat(method-references): add MethodReference demo using System.out::println

What
- Introduced `MethodReference` class demonstrating Java 8 method references.
- Created a list of student names (`Ram`, `Shyam`, `Tony`).
- Showcased:
  - Traditional lambda expression for printing elements.
  - Replacement with method reference `System.out::println` for cleaner syntax.

Why
- Method references provide a shorthand syntax for calling existing methods instead of writing explicit lambdas.
- They improve readability, reduce boilerplate, and make intent clearer when the lambda simply delegates to an existing method.

Logic
1. Created a `List<String>` using `Arrays.asList()`.
2. Demonstrated two approaches to iterate over the list:
   - Lambda: `students.forEach(x -> System.out.println(x));`
   - Method reference: `students.forEach(System.out::println);`
3. Both produce identical output, but method reference is more concise and idiomatic.

Real-life applications
- Commonly used in **Streams API** for cleaner code, e.g.:
  - `list.stream().map(String::toUpperCase).forEach(System.out::println);`
- Helpful in **event-driven systems** (e.g., Swing, JavaFX, Spring callbacks).
- Used for **constructor references** (`ClassName::new`) in dependency injection frameworks.
- Useful when working with **functional interfaces** like `Consumer`, `Supplier`, `Function`, etc.

Notes
- Four types of method references in Java:
  1. **Static methods** → `ClassName::staticMethod`.
  2. **Instance methods of a particular object** → `instance::method`.
  3. **Instance methods of an arbitrary object** → `ClassName::method`.
  4. **Constructor references** → `ClassName::new`.
- Method references require the target method signature to match the functional interface’s abstract method signature.

Signed-off-by: https://github.com/Someshdiwan <[email protected]>

Author: Someshdiwan

JAVA8/MethodReference/src/MethodReference.java

@@ -0,0 +1,13 @@
+import java.util.Arrays;
+import java.util.List;
+
+public class MethodReferenceDemo {
+    public static void main(String[] args) {
+
+        // Method reference --> use a method without invoking and in place of a lambda expression
+        List<String> students = Arrays.asList("Ram", "Shyam", "Tony");
+
+        //students.forEach(x -> System.out.println(x));
+        students.forEach(System.out::println);
+    }
+}