Test case for Ratpack handling startup failure

According to Ratpack API documentation for ratpack.service.Service:

Errors

If an onStart method errors, it will prevent the “application” from launching. ... When not in development mode, the exception will be thrown from the RatpackServer.start() method. If starting the app in a “main method”, this will prevent the JVM from starting.

So if an onStart method of a Service throws an exception, the expected result is that the JVM exit with non-zero exit code.

Sub-folders contain Groovy scripts using different ways to start Ratpack application.

groovy-script/

Ratpack runs directly from a plain Groovy script.

cd groovy-script
groovy run.groovy

The actual evidence matches the expected result.

groovy-entrypoint/

The Groovy script using ratpack.groovy.GroovyRatpackMain.

cd groovy-entrypoint
groovy run.groovy

The actual evidence matches the expected result.

uber-jar-groovy/

Maven project building an executable JAR using the same ratpack.groovy.GroovyRatpackMain entrypoint.

cd uber-jar-groovy
mvn package
java -jar target/ratpack-entrypoint.jar

The actual result: the JVM does not terminate. jconsole shows a thread that remains:

Name: ratpack-compute-1-1
State: RUNNABLE
Total blocked: 1  Total waited: 0

Stack trace: 
io.netty.channel.epoll.Native.epollWait0(Native Method)
io.netty.channel.epoll.Native.epollWait(Native.java:117)
io.netty.channel.epoll.EpollEventLoop.epollWait(EpollEventLoop.java:231)
io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:255)
io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:873)
ratpack.exec.internal.DefaultExecController$ExecControllerBindingThreadFactory.lambda$newThread$0(DefaultExecController.java:136)
ratpack.exec.internal.DefaultExecController$ExecControllerBindingThreadFactory$$Lambda$122/489070295.run(Unknown Source)
io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:144)
java.lang.Thread.run(Thread.java:745)

uber-jar-java/

Maven project building an executable JAR using the canonical ratpack.server.RatpackServer entrypoint.

cd uber-jar-java
mvn package
java -jar target/ratpack-entrypoint.jar

The actual result: like the previous example the JVM does not terminate.

Environment

Ratpack version: 1.4.6

$ uname -a
Linux ke-laptop 4.4.0-78-generic #99~14.04.2-Ubuntu SMP Thu Apr 27 18:49:46 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

$ java -version
openjdk version "1.8.0_111"
OpenJDK Runtime Environment (build 1.8.0_111-8u111-b14-3~14.04.1-b14)
OpenJDK 64-Bit Server VM (build 25.111-b14, mixed mode)

$ groovy -version
Groovy Version: 2.4.6 JVM: 1.8.0_111 Vendor: Oracle Corporation OS: Linux