fixes #13

Author: overheadhunter

README.md

@@ -62,6 +62,12 @@ requires org.cryptomator.siv;
 
 Because BouncyCastle classes are shaded, this library only depends on `java.base`.
 
+## Building
+
+This is a Maven project. To build it, run `mvn clean install`.
+
+Requires JDK 9+ at build time due to JPMS support.
+
 ## License
 Distributed under the MIT X Consortium license. See the LICENSE file for more info.
 

pom.xml

@@ -81,6 +81,27 @@
 
 	<build>
 		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-enforcer-plugin</artifactId>
+				<version>3.0.0-M2</version>
+				<executions>
+					<execution>
+						<id>enforce-java</id>
+						<goals>
+							<goal>enforce</goal>
+						</goals>
+						<configuration>
+							<rules>
+								<requireJavaVersion>
+									<message>You need at least JDK 9 to build this project.</message>
+									<version>[9,)</version>
+								</requireJavaVersion>
+							</rules>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
 			<plugin>
 				<artifactId>maven-compiler-plugin</artifactId>
 				<version>3.8.1</version>