JEP 500: Prepare to Make Final Mean Final

Author: ibrahimatay

README.md

@@ -11,7 +11,7 @@ This repository contains Java examples that are designed to track and document t
 ## Specifications & Practices
 
 * [Java 26](java-26/) (March, 2026)
-
+    * [JEP 500](java-26/src/main/java/JEP500PrepareToMakeFinalMeanFinal.java): Prepare to Make Final Mean Final
 * [Java 25](java-25/) (September, 2025)
   * [JEP 513](java-25/src/main/java/JEP513FlexibleConstructorBodies.java): Flexible Constructor Bodies
   * [JEP 512](java-25/src/main/java/JEP512CompactSourceFilesAndInstanceMainMethods.java): Compact Source Files and Instance Main Methods

java-26/src/main/java/JEP500PrepareToMakeFinalMeanFinal.java

@@ -0,0 +1,30 @@
+import java.lang.reflect.Field;
+
+// JEP 500: Prepare to Make Final Mean Final
+// https://openjdk.org/jeps/500
+
+public class JEP500PrepareToMakeFinalMeanFinal {
+    static void main() {
+        AppConfig config = new AppConfig();
+        System.out.println("1. Original Value: " + config.dbUrl);
+        try {
+            // We capture the 'dbUrl' field using the Reflection API
+            Field field = AppConfig.class.getDeclaredField("dbUrl");
+
+            // We disable Java's access checks (Opening the backdoor)
+            field.setAccessible(true);
+
+            // We force (hack) a change to the value of the 'final' variable
+            field.set(config, "jdbc:mysql://hacked-server:3306/stolen_db");
+
+            System.out.println("2. New Value (Changed): " + config.dbUrl);
+
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+}
+
+class AppConfig{
+    public final String dbUrl = "jdbc:postgresql://localhost:5432/mydb";
+}