2024 workshop - welcome empty map support

src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavacParser.java

@@ -2712,7 +2712,24 @@ List<JCExpression> arrayInitializerElements(int newpos, JCExpression t) {
     /** VariableInitializer = ArrayInitializer | Expression
      */
     public JCExpression variableInitializer() {
-        return token.kind == LBRACE ? arrayInitializer(token.pos, null) : parseExpression();
+        return this.variableInitializer(null);
+    }
+
+    public JCExpression variableInitializer(JCExpression type) {
+        if (token.kind == LBRACE) {
+            if (type instanceof JCIdent && ((JCIdent) type).name.equals(names.fromString("Map"))) {
+                return mapInitializer(token.pos);
+            } else {
+                return arrayInitializer(token.pos, null);
+            }
+        }
+        return parseExpression();
+    }
+
+    private JCExpression mapInitializer(int pos) {
+        accept(LBRACE);
+        accept(RBRACE);
+        return F.at(pos).NewMap();
     }
 
     /** ParExpression = "(" Expression ")"
@@ -3699,7 +3716,7 @@ JCVariableDecl variableDeclaratorRest(int pos, JCModifiers mods, JCExpression ty
 
         if (token.kind == EQ) {
             nextToken();
-            init = variableInitializer();
+            init = variableInitializer(type);
         }
         else if (reqInit) syntaxError(token.pos, Errors.Expected(EQ));
 

src/jdk.compiler/share/classes/com/sun/tools/javac/tree/TreeMaker.java

@@ -435,6 +435,17 @@ public JCNewArray NewArray(JCExpression elemtype,
         return tree;
     }
 
+    public JCExpression NewMap() {
+        JCFieldAccess util = new JCFieldAccess(Ident(names.fromString("java")), names.fromString("util"), null);
+        JCFieldAccess map = new JCFieldAccess(util, names.fromString("Map"), null);
+        JCFieldAccess of = new JCFieldAccess(map, names.fromString("of"), null);
+
+        JCMethodInvocation invocation = new JCMethodInvocation(List.nil(), of, List.nil());
+        invocation.pos = pos;
+
+        return invocation;
+    }
+
     public JCLambda Lambda(List<JCVariableDecl> params,
                            JCTree body)
     {

test/jdk/java/util/Map/ViqueenSyntaxSugarMapTest.java

@@ -0,0 +1,18 @@
+/*
+ * @test
+ * @run testng ViqueenSyntaxSugarMapTest
+ * @author Hasnae R.
+ */
+import java.util.Map;
+import org.testng.annotations.Test;
+
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertTrue;
+
+public class ViqueenSyntaxSugarMapTest {
+    @Test
+    public void testEmptyMap() {
+        Map empty = {};
+        assertTrue(empty.isEmpty());
+    }
+}