set JAVA_HOME or ensure java is in PATH code example
Example 1: set java home path
export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64
# Add JAVA bin directory to the PATH variable
export PATH=$PATH:$JAVA_HOME/bin
Example 2: find where JAVA_HOME is set
grep JAVA_HOME /etc/environment /etc/bash.bashrc /etc/profile.d/* /etc/profile