Test added to verify no duplicate compilation for java files

liberty-maven-plugin/src/it/dev-it/src/test/java/net/wasdev/wlp/test/dev/it/DevNoDuplicateCompilationTest.java

@@ -0,0 +1,138 @@
+/*******************************************************************************
+ * (c) Copyright IBM Corporation 2026.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *******************************************************************************/
+package net.wasdev.wlp.test.dev.it;
+
+import static org.junit.Assert.*;
+
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.FileWriter;
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class DevNoDuplicateCompilationTest extends BaseDevTest {
+
+    @BeforeClass
+    public static void setUpBeforeClass() throws Exception {
+        setUpBeforeClass("-DgenerateFeatures=true");
+    }
+
+    @AfterClass
+    public static void cleanUpAfterClass() throws Exception {
+        BaseDevTest.cleanUpAfterClass();
+    }
+
+    @Test
+    public void testNoDuplicateCompilation() throws Exception {
+        assertTrue(verifyLogMessageExists("Liberty is running in dev mode.", 10000));
+        assertTrue(verifyLogMessageExists(WEB_APP_AVAILABLE, 20000));
+
+        File srcHelloWorld = new File(tempProj, "src/main/java/com/demo/HelloWorld.java");
+        File targetHelloWorld = new File(targetDir, "classes/com/demo/HelloWorld.class");
+        assertTrue(srcHelloWorld.exists());
+        assertTrue(targetHelloWorld.exists());
+
+        // Count initial compilation messages
+        int initialCompilationCount = countOccurrences(COMPILATION_SUCCESSFUL, logFile);
+        int initialHotReloadCount = countOccurrences(SERVER_CONFIG_SUCCESS, logFile);
+
+        waitLongEnough();
+        long lastModified = targetHelloWorld.lastModified();
+
+        // Modify the Java file
+        String modification = "// Test modification for duplicate compilation check";
+        BufferedWriter javaWriter = null;
+        try {
+            javaWriter = new BufferedWriter(new FileWriter(srcHelloWorld, true));
+            javaWriter.append('\n');
+            javaWriter.append(modification);
+        } finally {
+            if (javaWriter != null) {
+                javaWriter.close();
+            }
+        }
+
+        assertTrue("Class file was not recompiled", waitForCompilation(targetHelloWorld, lastModified, 10000));
+        assertTrue("Source compilation message not found", 
+            verifyLogMessageExists(COMPILATION_SUCCESSFUL, 10000, ++initialCompilationCount));
+        assertTrue("Liberty hot reload message (CWWKZ0003I) not found",
+            verifyLogMessageExists(SERVER_CONFIG_SUCCESS, 10000, ++initialHotReloadCount));
+
+        Thread.sleep(3000);
+
+        // Count final compilation messages
+        int finalCompilationCount = countOccurrences(COMPILATION_SUCCESSFUL, logFile);
+        int finalHotReloadCount = countOccurrences(SERVER_CONFIG_SUCCESS, logFile);
+
+        assertEquals("Duplicate compilation detected - compilation happened more than once",
+            initialCompilationCount, finalCompilationCount);
+        assertEquals("Multiple hot reloads detected - should only reload once per change",
+            initialHotReloadCount, finalHotReloadCount);
+    }
+
+    @Test
+    public void testMultipleSequentialChanges() throws Exception {
+        assertTrue(verifyLogMessageExists("Liberty is running in dev mode.", 10000));
+        assertTrue(verifyLogMessageExists(WEB_APP_AVAILABLE, 20000));
+
+        File srcHelloWorld = new File(tempProj, "src/main/java/com/demo/HelloWorld.java");
+        File targetHelloWorld = new File(targetDir, "classes/com/demo/HelloWorld.class");
+        assertTrue(srcHelloWorld.exists());
+        assertTrue(targetHelloWorld.exists());
+
+        // Perform multiple sequential changes
+        for (int i = 1; i <= 3; i++) {
+            int compilationCountBefore = countOccurrences(COMPILATION_SUCCESSFUL, logFile);
+            int hotReloadCountBefore = countOccurrences(SERVER_CONFIG_SUCCESS, logFile);
+
+            waitLongEnough();
+            long lastModified = targetHelloWorld.lastModified();
+
+            // Modify the Java file
+            String modification = "// Test modification #" + i + " for duplicate compilation check";
+            BufferedWriter javaWriter = null;
+            try {
+                javaWriter = new BufferedWriter(new FileWriter(srcHelloWorld, true));
+                javaWriter.append('\n');
+                javaWriter.append(modification);
+            } finally {
+                if (javaWriter != null) {
+                    javaWriter.close();
+                }
+            }
+
+            assertTrue("Class file was not recompiled for change #" + i,
+                waitForCompilation(targetHelloWorld, lastModified, 10000));
+            assertTrue("Source compilation message not found for change #" + i,
+                verifyLogMessageExists(COMPILATION_SUCCESSFUL, 10000, ++compilationCountBefore));
+            assertTrue("Liberty hot reload message (CWWKZ0003I) not found for change #" + i,
+                verifyLogMessageExists(SERVER_CONFIG_SUCCESS, 10000, ++hotReloadCountBefore));
+
+            Thread.sleep(3000);
+
+            // Count compilation messages after change
+            int compilationCountAfter = countOccurrences(COMPILATION_SUCCESSFUL, logFile);
+            int hotReloadCountAfter = countOccurrences(SERVER_CONFIG_SUCCESS, logFile);
+
+            assertEquals("Duplicate compilation detected for change #" + i,
+                compilationCountBefore, compilationCountAfter);
+            assertEquals("Multiple hot reloads detected for change #" + i,
+                hotReloadCountBefore, hotReloadCountAfter);
+        }
+    }
+}