8374643: Fix reference to implMethodKind in LambdaToMethod debug printf statement

Reviewed-by: vromero, liach

src/jdk.compiler/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java

@@ -142,6 +142,9 @@ public class LambdaToMethod extends TreeTranslator {
     /** dump statistics about lambda code generation */
     private final boolean dumpLambdaToMethodStats;
 
+    /** dump statistics about lambda deserialization code generation */
+    private final boolean dumpLambdaDeserializationStats;
+
     /** force serializable representation, for stress testing **/
     private final boolean forceSerializable;
 
@@ -187,6 +190,7 @@ public class LambdaToMethod extends TreeTranslator {
         transTypes = TransTypes.instance(context);
         Options options = Options.instance(context);
         dumpLambdaToMethodStats = options.isSet("debug.dumpLambdaToMethodStats");
+        dumpLambdaDeserializationStats = options.isSet("debug.dumpLambdaDeserializationStats");
         attr = Attr.instance(context);
         forceSerializable = options.isSet("forceSerializable");
         boolean lineDebugInfo =
@@ -714,8 +718,9 @@ public class LambdaToMethod extends TreeTranslator {
         String implMethodName = refSym.getQualifiedName().toString();
         String implMethodSignature = typeSig(types.erasure(refSym.type));
 
+        int implMethodKind = refSym.referenceKind();
         JCExpression kindTest = eqTest(syms.intType, deserGetter("getImplMethodKind", syms.intType),
-                make.Literal(refSym.referenceKind()));
+                make.Literal(implMethodKind));
         ListBuffer<JCExpression> serArgs = new ListBuffer<>();
         int i = 0;
         for (Type t : indyType.getParameterTypes()) {
@@ -743,16 +748,16 @@ public class LambdaToMethod extends TreeTranslator {
             stmts = new ListBuffer<>();
             kInfo.deserializeCases.put(implMethodName, stmts);
         }
-        /* **
-        System.err.printf("+++++++++++++++++\n");
-        System.err.printf("*functionalInterfaceClass: '%s'\n", functionalInterfaceClass);
-        System.err.printf("*functionalInterfaceMethodName: '%s'\n", functionalInterfaceMethodName);
-        System.err.printf("*functionalInterfaceMethodSignature: '%s'\n", functionalInterfaceMethodSignature);
-        System.err.printf("*implMethodKind: %d\n", implMethodKind);
-        System.err.printf("*implClass: '%s'\n", implClass);
-        System.err.printf("*implMethodName: '%s'\n", implMethodName);
-        System.err.printf("*implMethodSignature: '%s'\n", implMethodSignature);
-        ****/
+        if (dumpLambdaDeserializationStats) {
+            log.note(pos, Notes.LambdaDeserializationStat(
+                    functionalInterfaceClass,
+                    functionalInterfaceMethodName,
+                    functionalInterfaceMethodSignature,
+                    implMethodKind,
+                    implClass,
+                    implMethodName,
+                    implMethodSignature));
+        }
         stmts.append(stmt);
     }
 

src/jdk.compiler/share/classes/com/sun/tools/javac/resources/compiler.properties

@@ -1701,6 +1701,17 @@ compiler.note.mref.stat.1=\
     alternate metafactory = {0}\n\
     bridge method = {1}
 
+# 0: string, 1: string, 2: string, 3: number, 4: string, 5: string, 6: string
+compiler.note.lambda.deserialization.stat=\
+    Generating lambda deserialization\n\
+    functionalInterfaceClass: {0}\n\
+    functionalInterfaceMethodName: {1}\n\
+    functionalInterfaceMethodSignature:{2}\n\
+    implMethodKind: {3}\n\
+    implClass: {4}\n\
+    implMethodName: {5}\n\
+    implMethodSignature: {6}
+
 compiler.note.note=\
     Note:\u0020
 

test/langtools/tools/javac/diags/examples/LambdaDeserializationStat.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2026, Google LLC and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+// key: compiler.note.lambda.deserialization.stat
+// options: --debug=dumpLambdaDeserializationStats
+
+import java.io.Serializable;
+
+class LambdaDeserializationStat {
+    Runnable r = (Runnable & Serializable) () -> {};
+}

test/langtools/tools/javac/lambda/SerializableObjectMethods.java

@@ -25,7 +25,7 @@
  * @test
  * @bug 8282080
  * @summary Check that serializable lambdas referring to j.l.Object methods work.
- * @compile SerializableObjectMethods.java
+ * @compile/ref=SerializableObjectMethods.out -XDrawDiagnostics --debug=dumpLambdaDeserializationStats SerializableObjectMethods.java
  * @run main SerializableObjectMethods
  */
 import java.io.ByteArrayInputStream;

test/langtools/tools/javac/lambda/SerializableObjectMethods.out

@@ -0,0 +1,4 @@
+SerializableObjectMethods.java:59:35: compiler.note.lambda.deserialization.stat: SerializableObjectMethods$F, apply, (Ljava/lang/Object;)Ljava/lang/Object;, 5, java/lang/Object, hashCode, ()I
+SerializableObjectMethods.java:60:35: compiler.note.lambda.deserialization.stat: SerializableObjectMethods$F, apply, (Ljava/lang/Object;)Ljava/lang/Object;, 9, SerializableObjectMethods$I2, hashCode, ()I
+- compiler.note.unchecked.filename: SerializableObjectMethods.java
+- compiler.note.unchecked.recompile