Fix parsing of service provider file (#3841).

modules/flowable-osgi/pom.xml

@@ -201,6 +201,11 @@
             <artifactId>junit-jupiter-api</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <properties>

modules/flowable-osgi/src/main/java/org/flowable/osgi/Extender.java

@@ -21,11 +21,13 @@
 import java.io.InputStreamReader;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Enumeration;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Predicate;
 
 import javax.script.ScriptEngine;
 import javax.script.ScriptEngineFactory;
@@ -367,9 +369,13 @@ public void unregister() {
         @Override
         public ScriptEngine resolveScriptEngine(String name) {
             try {
-                BufferedReader in = new BufferedReader(new InputStreamReader(configFile.openStream()));
-                String className = in.readLine();
-                in.close();
+                String className;
+                try (var input = configFile.openStream()) {
+                    className = new BufferedReader(new InputStreamReader(input, StandardCharsets.UTF_8)).lines()
+                            .map(line -> line.split("#", 2)[0].trim())
+                            .filter(Predicate.not(String::isBlank))
+                            .findFirst().orElse(null);
+                }
                 Class<?> cls = bundle.loadClass(className);
                 if (!ScriptEngineFactory.class.isAssignableFrom(cls)) {
                     throw new IllegalStateException("Invalid ScriptEngineFactory: " + cls.getName());

modules/flowable-osgi/src/test/java/org/flowable/osgi/BundleScriptEngineResolverTest.java

@@ -0,0 +1,67 @@
+/* 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 org.flowable.osgi;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.net.URL;
+import java.util.List;
+
+import javax.script.ScriptEngine;
+import javax.script.ScriptEngineFactory;
+
+import org.flowable.osgi.Extender.BundleScriptEngineResolver;
+import org.junit.Test;
+import org.osgi.framework.Bundle;
+
+/**
+ * Test processing of service provider configuration file.
+ */
+public class BundleScriptEngineResolverTest {
+
+    @Test
+    public void testResolveScriptEngine() throws Exception {
+        ScriptEngineFactory factory = mock(ScriptEngineFactoryMock.class);
+        Bundle bundle = mock(Bundle.class);
+        when(bundle.loadClass(eq("org.flowable.ScriptEngineFactoryMock"))).thenAnswer(answer -> factory.getClass());
+        URL configFile = getClass().getClassLoader().getResource("META-INF/services/javax.script.ScriptEngineFactory");
+        BundleScriptEngineResolver resolver = new BundleScriptEngineResolver(bundle, configFile);
+        ScriptEngine resolvedEngine = resolver.resolveScriptEngine("mockengine");
+        assertNotNull(resolvedEngine);
+        assertEquals("mockengine", resolvedEngine.get("name"));
+    }
+
+    /**
+     * Script engine factory providing mock script engine.
+     */
+    static abstract class ScriptEngineFactoryMock implements ScriptEngineFactory {
+
+        @Override
+        public List<String> getNames() {
+            return List.of("mockengine");
+        }
+
+        @Override
+        public ScriptEngine getScriptEngine() {
+            ScriptEngine engine = mock(ScriptEngine.class);
+            when(engine.get(eq("name"))).thenReturn("mockengine");
+            return engine;
+        }
+
+    }
+
+}

modules/flowable-osgi/src/test/resources/META-INF/services/javax.script.ScriptEngineFactory

@@ -0,0 +1,4 @@
+# Comments, tabs and spaces should be ignored
+# See java.util.ServiceLoader
+
+	org.flowable.ScriptEngineFactoryMock # should be also ignored