$ export JAVA_HOME=/opt/jdk-11
$ export PATH=$JAVA_HOME/bin:$PATH

$ java -version
openjdk version "11" 2018-09-25
...

$ export M2_HOME=/opt/maven-3.6
$ export PATH=$M2_HOME/bin:$PATH

$ mvn --version
Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)
...

$ git clone https://github.com/vakuum/polyglot-java.git

$ cd polyglot-java
$ cat all/src/main/java/polyglot/All.java
$ mvn clean install -DskipTests
$ mvn exec:java --projects all
...
Hello, I am Java!
Clojure: Hello Java!
Frege: Hello Java!
Gosu: Hello Java!
Groovy: Hello Java!
Hoot: Hello Java!
Java: Hello Java!
Kotlin: Hello Java!
Python: Hello Java!
Ruby: Hello Java!
Scala: Hello Java!
Xtend: Hello Java!
...

$ cd polyglot-java
$ mvn clean install -DskipTests
$ mvn exec:java --projects clojure
...
Clojure: Hello Clojure!
...

$ mvn exec:java --projects frege
...
Frege: Hello Frege!
...

$ mvn exec:java --projects gosu
...
Gosu: Hello Gosu!
...

$ mvn exec:java --projects groovy
...
Groovy: Hello Groovy!
...

$ mvn exec:java --projects hoot
...
Hoot: Hello Hoot!
...

$ mvn exec:java --projects java
...
Java: Hello Java!
...

$ mvn exec:java --projects kotlin
...
Kotlin: Hello Kotlin!
...

$ mvn exec:java --projects python
...
Python: Hello Python!
...

$ mvn exec:java --projects ruby
...
Ruby: Hello Ruby!
...

$ mvn exec:java --projects scala
...
Scala: Hello Scala!
...

$ mvn exec:java --projects xtend
...
Xtend: Hello Xtend!
...

$ cd polyglot-java
$ mvn clean install -DskipTests
$ mvn package assembly:single --projects all -DskipTests
$ java -jar all/target/polyglot-java.jar
...
Hello, I am Java!
Clojure: Hello Java!
Frege: Hello Java!
Gosu: Hello Java!
Groovy: Hello Java!
Hoot: Hello Java!
Java: Hello Java!
Kotlin: Hello Java!
Python: Hello Java!
Ruby: Hello Java!
Scala: Hello Java!
Xtend: Hello Java!
...

$ cd polyglot-java
$ cat all/src/test/java/polyglot/TestAll.java
$ mvn clean install -DskipTests
$ mvn test --projects all
...
Tests run: 12, Failures: 0, Errors: 0, Skipped: 0
...