#feat: Add demo for JEP 357 - Migrate from Mercurial to Git

src/main/java/org/javademos/init/Java16.java

@@ -34,6 +34,10 @@ public static ArrayList<IDemo> getDemos() {
         java16DemoPool.add(new VectorAPIDemo());
         // JEP 347
         java16DemoPool.add(new Cpp14FeaturesDemo());
+        // Inside the list/map initialization in the JDK 16 helper file
+            // ... other demos ...
+        demos.add(new org.javademos.java16.jep357.MercurialToGitMigration()); // JEP 357
+        // ... other demos ...
         // JEP 380
         java16DemoPool.add(new UnixDomainSocketsDemo());
         // JEP 386 

src/main/java/org/javademos/java16/jep357/MercurialToGitMigration.java

@@ -0,0 +1,35 @@
+package org.javademos.java16.jep357;
+
+import org.javademos.commons.IDemo;
+
+/**
+ * ## JEP 357: Migrate from Mercurial to Git
+ *
+ * ### History
+ * * JDK 16: Delivered
+ *
+ * ### Links
+ * * [JEP 357](https://openjdk.org/jeps/357)
+ * * [JEP 369: Migrate to GitHub](https://openjdk.org/jeps/369)
+ *
+ * This JEP was purely an infrastructure change for the OpenJDK community.
+ * There are no Java language features or APIs to demonstrate.
+ */
+public class MercurialToGitMigration implements IDemo {
+
+    @Override
+    public void demo() {
+        info(357);
+
+        System.out.println("This JEP was an infrastructure project to migrate the OpenJDK Community's source code repositories.");
+        System.out.println("The migration was from Mercurial (hg) to Git.");
+        System.out.println();
+        System.out.println("Key Goals:");
+        System.out.println("1. Migrate all single-repository OpenJDK Projects.");
+        System.out.println("2. Preserve all version control history, including tags.");
+        System.out.println("3. Port internal tools (like 'jcheck') to work with Git.");
+        System.out.println();
+        System.out.println("This change did not introduce any new Java language features or APIs, " +
+                "but was a critical step for the community, leading to JEP 369 (Migrate to GitHub).");
+    }
+}

src/main/resources/JDK16Info.json

@@ -15,6 +15,14 @@
     "link": false,
     "code": false
   },
+  {
+  "no": 357,
+  "jdk": 16,
+  "name": "Migrate from Mercurial to Git",
+  "description": "Migrate the OpenJDK Community's source code repositories from Mercurial (hg) to Git.",
+  "link": false,
+  "code": false
+ },
   {
     "jep": 380,
     "jdk": 16,