Scenario:

• Running .postinstall.tomcat

  $ sudo ./.postinstall.tomcat
   ...
   BORING STUFF
   ...
  -----------------------------------------------------------------------
   NOTICE
  -----------------------------------------------------------------------
  
   JAVA_HOME environment variable is not set.
   Either set the  JAVA_HOME  or edit the configuration
   scripts inside `/opt/jbcs2/jws-3.1/etc/sysconfig' directory
   and set the JAVA_HOME to the installed JDK location.
  
  Done
  

• As I run postinstall with sudo and sudo don't have JAVA_HOME set, I get a notice about my empty JAVA_HOME variable.
• Current user has correctly set JAVA_HOME

  $ echo $JAVA_HOME
  /java/installation/location/jdk1.7.0_last
  

• However running

  // $JWS_HOME/sbin
  $ sudo ./tomcat8 start
  Oracle Corporation      SunOS 5.11      11.3    November 2016
  Using CATALINA_BASE:   /opt/jbcs2/jws-3.1/share/tomcat8
  Using CATALINA_HOME:   /opt/jbcs2/jws-3.1/share/tomcat8
  Using CATALINA_TMPDIR: /var/cache/tomcat8/temp
  Using JRE_HOME:        /usr
  Using CLASSPATH:       /opt/jbcs2/jws-3.1/share/tomcat8/bin/bootstrap.jar:/opt/jbcs2/jws-3.1/share/tomcat8/bin/tomcat-juli.jar
  Using CATALINA_PID:    /var/run/tomcat8.pid
  

  Gives

  Using JRE_HOME:        /usr
  

• And my set JAVA_HOME is not used and output may be unexpected

Issue:
Script $JWS_HOME/sbin/tomcat<VERSION> starts tomcat under user tomcat with it's own
enviroment so your set variables will not be used.
Issue fix:
File $JWS_HOME/sbin/tomcat<VERSION>

66 --- $SU - $TOMCAT_USER -c "$TOMCAT_SCRIPT $XCMD $ARGS"
66 +++ $SU  $TOMCAT_USER -c "$TOMCAT_SCRIPT $XCMD $ARGS"

SU variable may be "/sbin/runuser" or "su". I haven't tried "/sbin/runuser". However,
su without dash will create expected output. There is need to try runuser script if he is ok with such change.