The legacy web application which I want to dockerise uses some old classes like com/sun/image/codec/jpeg/ImageFormatException which were supported till Java SE7.
Now in the docker container default jdk getting (on installing tomcat-6 container) is
java version "1.7.0_131"
OpenJDK Runtime Environment (IcedTea 2.6.9) (7u131-2.6.9-2~deb8u1)
OpenJdk doesn't support these classes
I used update-alternatives to install Oracle Jdk7.80
After loading container, on giving java -version I am getting
java version "1.7.0_80"
Java(TM) SE Runtime Environment (build 1.7.0_80-b15)
Java HotSpot(TM) 64-Bit Server VM (build 24.80-b11, mixed mode)
However, echo $JAVA_HOME after entering the container gives /docker-java-home/jre which again points to OpenJdk. How can I set JAVA_HOME to the Oracle Jdk home that I installed?