如何在tomcat服务器中升级Java？

Question

My server is in a Unix environment. And I'm using tomcat server. I'm trying to upgrade the Java version, but tomcat is not starting after the upgrade.

which java still gives the old version.

Below is the script for java pointing to tomcat:

if [ -z "$JAVA_HOME" -a -z "$JRE_HOME" ]; then
    some script
fi
else
    JAVA_PATH=`which java 2>/dev/null`
    if [ "x$JAVA_PATH" != "x" ]; then
      JAVA_PATH=`dirname $JAVA_PATH 2>/dev/null`
      JRE_HOME=`dirname $JAVA_PATH 2>/dev/null`
    fi
    if [ "x$JRE_HOME" = "x" ]; then
      if [ -x /usr/bin/java ]; then
        JRE_HOME=/usr
      fi
    fi
  fi
  if [ -z "$JAVA_HOME" -a -z "$JRE_HOME" ]; then
    echo "Neither the JAVA_HOME nor the JRE_HOME environment variable is defined"
    echo "At least one of these environment variable is needed to run this program"
    exit 1
  fi
fi

Answer 1

Tomcat uses JAVA_HOME variable to get the path for Java . So the question drills down to how you set JAVA_HOME and where to set it ?

You might find JAVA_HOME under less /etc/profile.d/jdk.sh depending on which shell you are using . I am using cshell so its under /etc/profile.d/jdk.csh

If you will check less /etc/profile , this is the file which is loaded when a user logs in. There is a variable called as PATH the value for which might be something like /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin so you can access any executable under these paths.

The line in ponder in /etc/profile is for i in /etc/profile.d/*.sh from where all the variable (in case of bash ) will be loaded into the environment. Also, it's important to note, if you are setting values here these variable will be set for all the users not just for one.

You might find this and this answer useful.