* Installing JDK, not just JRE

* Added usage examples in README

devbox/Dockerfile

@@ -1,7 +1,7 @@
 FROM itzg/ubuntu-openjdk-7
 
 RUN apt-get update
-RUN apt-get install -yq git curl wget unzip
+RUN apt-get install -yq git curl wget unzip openjdk-7-jdk
 
 ENV MAVEN_VER 3.2.2
 ENV NODEJS_VER 0.10.29
@@ -24,4 +24,6 @@ VOLUME ["/shared"]
 
 RUN curl -s get.gvmtool.net | bash
 
+RUN apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+
 CMD bash

devbox/README.md

@@ -3,3 +3,23 @@ Provides a development/build environment for Java, Groovy, and NodeJS.
 * Provides 'gvm' for Groovy (and more) installation management
 * Provides 'nave' for NodeJS installation management
 * Pre-installs the latest NodeJS via nave
+
+## Using the persistent/shared workarea
+
+Since devbox containers are intended to be disposable, the image is configured 
+with a "volume" at `/shared`. 
+
+There are a couple of ways you can leverage that volume. Either attach it to
+a host-local directory:
+
+    docker run -it -v $(pwd)/workarea:/shared --rm itzg/devbox
+
+or run a "base" container and mounts the `/shared` from that onto any
+subsequent containers:
+
+    docker run --name devbox-base itzg/devbox touch /shared/READY
+    ...later...
+    docker run -it --volumes-from devbox-base --rm itzg/devbox
+
+**NOTE** I am using the `--rm` option so the devbox containers will be truly
+"burn after use".