feat: add Product.java

src/main/java/Product.java

@@ -0,0 +1,23 @@
+public class Product {
+    private final int productID;
+    private final String productName;
+    private final double price;
+
+    public Product(int productID, String productName, double price) {
+        this.productID = productID;
+        this.productName = productName;
+        this.price = price;
+    }
+
+    public int getProductID() {
+        return productID;
+    }
+
+    public String getProductName() {
+        return productName;
+    }
+
+    public double getPrice() {
+        return price;
+    }
+}