As of 30Jul, 2018 to fix the above issue, one can configure the java version used within maven to any up to JDK/11 and make use of the maven-compiler-plugin:3.8.0
to specify a release of either 9,10,11 without any explicit dependencies.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
<configuration>
<release>11</release> <!--or <release>10</release>-->
</configuration>
</plugin>
Note:- The default value for source/target has been lifted from 1.5 to 1.6 with this version. -- release notes.
Edit [30.12.2018]
In fact, you can make use of the same version of maven-compiler-plugin
while compiling the code against JDK/12 as well.
More details and a sample configuration in how to Compile and execute a JDK preview feature with Maven.