Fix ZIPCompressedMessage compression level to be per-instance

Agent-Logs-Url: https://github.com/jMonkeyEngine/jmonkeyengine/sessions/52dd3a6c-82f7-4d23-8ba2-a85f8b13e5ac

Co-authored-by: riccardobl <4943530+riccardobl@users.noreply.github.com>

Author: Copilot

jme3-networking/src/main/java/com/jme3/network/message/ZIPCompressedMessage.java

@@ -41,7 +41,8 @@
  */
 @Serializable()
 public class ZIPCompressedMessage extends CompressedMessage {
-    private static int compressionLevel = 6;
+    private static int defaultCompressionLevel = 6;
+    private int compressionLevel = defaultCompressionLevel;
 
     /**
      * Creates an empty ZIP-compressed message for serialization.
@@ -67,21 +68,31 @@ public ZIPCompressedMessage(Message msg) {
      */
     public ZIPCompressedMessage(Message msg, int level) {
         super(msg);
-        setLevel(level);
+        this.compressionLevel = level;
     }
 
     /**
-     * Set the compression level, where 1 is the best compression but slower and 9 is the weakest
-     *  compression but the quickest. Default is 6.
+     * Set the default compression level for newly created ZIP compressed messages,
+     * where 1 is the best compression but slower and 9 is the weakest compression
+     * but the quickest. Default is 6.
      *
      * @param level The level.
      */
     public static void setLevel(int level) {
+        defaultCompressionLevel = level;
+    }
+
+    /**
+     * Sets this message's compression level.
+     *
+     * @param level The level.
+     */
+    public void setCompressionLevel(int level) {
         compressionLevel = level;
     }
 
     /**
-     * Returns the currently globally configured ZIP compression level.
+     * Returns this message's configured ZIP compression level.
      *
      * @return the ZIP compression level
      */

jme3-networking/src/test/java/com/jme3/network/message/ZIPCompressedMessageTest.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2009-2026 jMonkeyEngine
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
+ *   may be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package com.jme3.network.message;
+
+import com.jme3.network.AbstractMessage;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class ZIPCompressedMessageTest {
+
+    @AfterEach
+    public void resetCompressionDefault() {
+        ZIPCompressedMessage.setLevel(6);
+    }
+
+    @Test
+    public void testMessageSpecificCompressionLevelDoesNotLeakToOtherMessages() {
+        ZIPCompressedMessage.setLevel(6);
+
+        ZIPCompressedMessage first = new ZIPCompressedMessage(new TestMessage());
+        ZIPCompressedMessage second = new ZIPCompressedMessage(new TestMessage(), 1);
+        ZIPCompressedMessage third = new ZIPCompressedMessage(new TestMessage());
+
+        assertEquals(6, first.getLevel());
+        assertEquals(1, second.getLevel());
+        assertEquals(6, third.getLevel());
+    }
+
+    @Test
+    public void testStaticLevelRemainsDefaultForNewMessages() {
+        ZIPCompressedMessage.setLevel(9);
+
+        ZIPCompressedMessage first = new ZIPCompressedMessage(new TestMessage());
+
+        ZIPCompressedMessage.setLevel(4);
+        ZIPCompressedMessage second = new ZIPCompressedMessage(new TestMessage());
+
+        assertEquals(9, first.getLevel());
+        assertEquals(4, second.getLevel());
+    }
+
+    private static class TestMessage extends AbstractMessage {
+    }
+}