Solve #440

pf4j/pom.xml

@@ -21,6 +21,10 @@
                 <artifactId>maven-compiler-plugin</artifactId>
                 <configuration>
                     <compilerArgument>-proc:none</compilerArgument>
+                    <!-- Only required when JAVA_HOME isn't at least Java 9 and when haven't configured the maven-toolchains-plugin -->
+                    <jdkToolchain>
+                        <version>9</version>
+                    </jdkToolchain>
                 </configuration>
                 <executions>
                     <!-- compile everything for Java 8 except the module-info.java -->

pf4j/src/main/java/module-info.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2012-present the original author or authors.
+ *
+ * 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.
+ */
+
+/**
+ * Module descriptor for PF4J.
+ *
+ * @author Decebal Suiu
+ * @author Andreas Rudolph
+ */
+module org.pf4j {
+    requires java.base;
+
+    // provides javax.annotation
+    requires java.compiler;
+
+    // provided by the ASM library
+    requires org.objectweb.asm;
+
+    // The SLF4J library currently does not provide a module.
+    // Version 1.8 provides a module called "org.slf4j". But this version is
+    // currently in beta stage. Therefore I'm not sure, if we already like to
+    // use it.
+    requires slf4j.api;
+
+    // The java-semver library currently does not provide a module.
+    // Maybe we should send them a pull request, that at least they provide an
+    // automatic module name in their MANIFEST file.
+    requires java.semver;
+
+    // Maybe we should reconsider the package hierarchy, that only classes are
+    // exported, which are required by 3rd party developers.
+    exports org.pf4j;
+    exports org.pf4j.processor;
+}