8358624: ImmutableDescriptor violates equals/hashCode contract after deserialization

src/java.management/share/classes/javax/management/ImmutableDescriptor.java

@@ -138,6 +138,7 @@ private Object readResolve() throws InvalidObjectException {
         if (names == null || values == null || names.length != values.length)
             bad = true;
         if (!bad) {
+            hashCode = -1; // Force recalculation
             if (names.length == 0 && getClass() == ImmutableDescriptor.class)
                 return EMPTY_DESCRIPTOR;
             final Comparator<String> compare = String.CASE_INSENSITIVE_ORDER;
@@ -441,12 +442,14 @@ public Descriptor clone() {
      */
     public final void setFields(String[] fieldNames, Object[] fieldValues)
         throws RuntimeOperationsException {
+
         if (fieldNames == null || fieldValues == null)
             illegal("Null argument");
         if (fieldNames.length != fieldValues.length)
             illegal("Different array sizes");
         for (int i = 0; i < fieldNames.length; i++)
             checkIllegalFieldName(fieldNames[i]);
+        hashCode = -1;
         for (int i = 0; i < fieldNames.length; i++)
             setField(fieldNames[i], fieldValues[i]);
     }
@@ -462,10 +465,12 @@ public final void setFields(String[] fieldNames, Object[] fieldValues)
      */
     public final void setField(String fieldName, Object fieldValue)
         throws RuntimeOperationsException {
+
         checkIllegalFieldName(fieldName);
         int i = fieldIndex(fieldName);
         if (i < 0)
             unsupported();
+        hashCode = -1;
         Object value = values[i];
         if ((value == null) ?
                 (fieldValue != null) :
@@ -485,6 +490,7 @@ public final void setField(String fieldName, Object fieldValue)
      * be an {@link UnsupportedOperationException}.
      */
     public final void removeField(String fieldName) {
+        hashCode = -1;
         if (fieldName != null && fieldIndex(fieldName) >= 0)
             unsupported();
     }

test/jdk/javax/management/descriptor/ImmutableDescriptorSerialHashCodeTest.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2025, Oracle 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.
+ */
+
+/*
+ * @test
+ * @bug 8358624
+ * @summary Test ImmutableDescriptor hashcode and serialization
+ *
+ * @run main ImmutableDescriptorSerialHashCodeTest
+ */
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import javax.management.Descriptor;
+import javax.management.ImmutableDescriptor;
+
+public class ImmutableDescriptorSerialHashCodeTest {
+    public static void main(String[] args) throws Exception {
+
+        Descriptor d1 = new ImmutableDescriptor("a=aval", "B=Bval", "cC=cCval");
+        Descriptor d2 = new ImmutableDescriptor("a=aval", "B=Bval", "cC=cCval");
+
+        test (d1, d2, "Objects created from same String"); // Sanity check
+        Descriptor dSer = serialize(d1);
+        test(d1, dSer, "After serialization"); // Actual test
+        System.out.println("PASSED");
+    }
+
+    /**
+      * Test that two Descriptor objects are both equal, and have equal hashcodes.
+      */
+    private static void test(Descriptor d1, Descriptor d2, String msg) throws Exception {
+        if (!d1.equals(d2)) {
+            throw new RuntimeException(msg + ": Descriptors not equal: " +
+                    "\nd1: " + d1 +
+                    "\nd2: " + d2);
+        }
+        if (d1.hashCode() != d2.hashCode()) {
+            throw new RuntimeException(msg + ": Hash code mismatch.  hash1: " + d1.hashCode()
+                                + ", hash2: " + d2.hashCode());
+        }
+    }
+
+    private static <T> T serialize(T x) throws Exception {
+        ByteArrayOutputStream bout = new ByteArrayOutputStream();
+        ObjectOutputStream oout = new ObjectOutputStream(bout);
+        oout.writeObject(x);
+        oout.close();
+        byte[] bytes = bout.toByteArray();
+        ByteArrayInputStream bin = new ByteArrayInputStream(bytes);
+        ObjectInputStream oin = new ObjectInputStream(bin);
+        return (T) oin.readObject();
+    }
+}