ServiceMonitor - Migration

An example application for my book The Java 9 Module System. The Service Monitor is an application that observes a hypothetical network of microservices by

contacting individual services
collecting and aggregating diagnostic data into statistics
persisting statistics
making statistics available via REST

It is split into a number of modules that focus on specific concerns. Each module has its own directory that contains the known folder structure, e.g. src/main/java.

It was developed as a Java 8 application and now needs to be made compatible with Java 9 and then be modularized.

Branches

Each of the branches contains a different version of the project:

master: starting point, Java 8
migrated: Java 9 compatible
modularized: partially modularized

Build and Execution

In the project's root folder:

to build: mvn clean install
to run: java -cp 'monitor/target/libs/*':'monitor/target/main-1.0-SNAPSHOT.jar' monitor.Main
to contact REST endpoints:
- curl http://localhost:4567/stats/json
- curl http://localhost:4567/stats/json64 | base64 -d
- curl http://localhost:4567/stats/xml

Troubles

Migration

internal BASE64Encoder is gone ~> use Base64.getEncoder instead
JAXB API is not present ~> add java.xml.bind
Common annotations are not present ~> add java.xml.ws.annotations
split package: javax.annotation between java.xml.ws.annotations and jsr-305 ~> patch java.xml.ws.annotations
old version of Mockito causes warnings ~> update to newer version
application class loader is no longer a URLClassLoader

Modularization