resolve #11

Author: Dmytro Aleksandrov

openjdk-6-jdk/Dockerfile

@@ -17,5 +17,8 @@ RUN \
 # Define working directory.
 WORKDIR /data
 
+# Define commonly used JAVA_HOME variable
+ENV JAVA_HOME /usr/lib/jvm/java-6-openjdk-amd64
+
 # Define default command.
 CMD ["bash"]

openjdk-6-jre/Dockerfile

@@ -17,5 +17,8 @@ RUN \
 # Define working directory.
 WORKDIR /data
 
+# Define commonly used JAVA_HOME variable
+ENV JAVA_HOME /usr/lib/jvm/java-6-openjdk-amd64
+
 # Define default command.
 CMD ["bash"]

openjdk-7-jdk/Dockerfile

@@ -17,5 +17,8 @@ RUN \
 # Define working directory.
 WORKDIR /data
 
+# Define commonly used JAVA_HOME variable
+ENV JAVA_HOME /usr/lib/jvm/java-7-openjdk-amd64
+
 # Define default command.
 CMD ["bash"]

openjdk-7-jre/Dockerfile

@@ -17,5 +17,8 @@ RUN \
 # Define working directory.
 WORKDIR /data
 
+# Define commonly used JAVA_HOME variable
+ENV JAVA_HOME /usr/lib/jvm/java-7-openjdk-amd64
+
 # Define default command.
 CMD ["bash"]

oracle-java6/Dockerfile

@@ -19,5 +19,8 @@ RUN \
 # Define working directory.
 WORKDIR /data
 
+# Define commonly used JAVA_HOME variable
+ENV JAVA_HOME /usr/lib/jvm/java-6-oracle
+
 # Define default command.
 CMD ["bash"]

oracle-java7/Dockerfile

@@ -19,5 +19,8 @@ RUN \
 # Define working directory.
 WORKDIR /data
 
+# Define commonly used JAVA_HOME variable
+ENV JAVA_HOME /usr/lib/jvm/java-7-oracle
+
 # Define default command.
 CMD ["bash"]

oracle-java8/Dockerfile

@@ -19,5 +19,8 @@ RUN \
 # Define working directory.
 WORKDIR /data
 
+# Define commonly used JAVA_HOME variable
+ENV JAVA_HOME /usr/lib/jvm/java-8-oracle
+
 # Define default command.
 CMD ["bash"]