Added Java module declaration, updated POM to compile module as Java 9 but all other classes as Java 8.

java/pom.xml

@@ -8,8 +8,6 @@
 	<packaging>jar</packaging>
 	<properties>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-		<maven.compiler.source>1.8</maven.compiler.source>
-		<maven.compiler.target>1.8</maven.compiler.target>
 	</properties>
 	
 	
@@ -19,6 +17,28 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-compiler-plugin</artifactId>
+				<version>3.8.1</version>
+				<executions>
+					<execution>
+						<id>default-compile</id>
+						<configuration>
+							<release>9</release>
+						</configuration>
+					</execution>
+					<execution>
+						<id>java8-compile</id>
+						<goals>
+							<goal>compile</goal>
+						</goals>
+						<configuration>
+							<source>1.8</source>
+							<target>1.8</target>
+							<excludes>
+								<exclude>module-info.java</exclude>
+							</excludes>
+						</configuration>
+					</execution>
+				</executions>
 			</plugin>
 			
 			<plugin>

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

@@ -0,0 +1,29 @@
+/* 
+ * QR Code generator library (Java)
+ * 
+ * Copyright (c) Project Nayuki. (MIT License)
+ * https://www.nayuki.io/page/qr-code-generator-library
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ * - The above copyright notice and this permission notice shall be included in
+ *   all copies or substantial portions of the Software.
+ * - The Software is provided "as is", without warranty of any kind, express or
+ *   implied, including but not limited to the warranties of merchantability,
+ *   fitness for a particular purpose and noninfringement. In no event shall the
+ *   authors or copyright holders be liable for any claim, damages or other
+ *   liability, whether in an action of contract, tort or otherwise, arising from,
+ *   out of or in connection with the Software or the use or other dealings in the
+ *   Software.
+ */
+
+
+module io.nayuki.qrcodegen {
+	
+	exports io.nayuki.qrcodegen;
+	
+}