feat: add ThisWord example demonstrating usage of 'this' keyword in constructors

Implemented ThisWord.java to illustrate how the 'this' keyword differentiates
instance variables from constructor parameters. Includes an example of object
creation and field initialization representing an account holder scenario.

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

Author: Someshdiwan

Section16StaticFinal/src/ThisWord.java

@@ -0,0 +1,19 @@
+class ThisWord {
+    // Instance variables for the account holder's name and balance
+    String accountHolderName;
+    double accountBalance;
+
+    // Parameterized constructor to initialize name and balance using 'this' keyword
+    public ThisWord(String name, double balance) {
+        this.accountHolderName = name;  // 'this' refers to the instance variable accountHolderName
+        this.accountBalance = balance;  // 'this' refers to the instance variable accountBalance
+    }
+
+    public static void main(String[] args) {
+        // Create an object of ThisWord class with a parameterized constructor
+        ThisWord account = new ThisWord("Alice", 1500.0);  // Initializing with name and balance
+
+        System.out.println("Account Holder: " + account.accountHolderName);  // Accessing the name
+        System.out.println("Account Balance: " + account.accountBalance);  // Accessing the balance
+    }
+}