Dockerized Java EE 8 Apps With Glassfish 5.0
There's a shiny new base GlassFish Docker image specifically made for Java EE 8 app development. Take a look at what it offers and how you can put it to use.
oracle/glassfish.
The Dockerfile of a zero-dependency Java EE 8 application looks like as follows:
FROM oracle/glassfish:5.0
COPY target/application.war $GLASSFISH_HOME/glassfish/domains/domain1/autodeploy/A Docker container of that image starts the application server and auto-deploys our application.
application.war is a thin WAR deployment artifact — what speeds up build, publishing and deployment times. The WAR file comprises only application-specific classes — no implementation-specific JAR files. If needed, any dependencies are added on top of the base image — before the actual application.
Imagine, we want to add the Prometheus Java API:
FROM oracle/glassfish:5.0
ENV GLASSFISH_LIB=$GLASSFISH_HOME/glassfish/domains/domain1/lib/ext/
# add Prometheus Java API
COPY .../simpleclient-0.0.26.jar $GLASSFISH_LIB
COPY .../simpleclient_common-0.0.26.jar $GLASSFISH_LIB
COPY target/application.war $GLASSFISH_HOME/glassfish/domains/domain1/autodeploy/The application can already use Java EE 8 standards such as JSON-B. The provided dependency is javax:javaee-api:8.0 — same as the Java EE 7 API with an incremented version number.
To see a full example that uses Prometheus, please see Prometheus with Java EE. That example can also run on Java EE 8 and GlassFish 5 by updating the API version to 8.0 and the Docker base image to oracle/glassfish.
Have fun developing Java EE 8 applications for Docker!
Published at DZone with permission of Sebastian Daschner. See the original article here.
Opinions expressed by DZone contributors are their own.