How to update .bashrc with PATH

Question

I have installed a new JRE on my RedHat linux system.

lsb_release -i -r
Distributor ID: CentOS
Release:    6.5

I have updated the symbolic links pointing to the desired Java installation:

ls -l /usr/bin/java
lrwxrwxrwx. 1 root root 21 Jul 21 16:27 /usr/bin/java -> /usr/java/jre1.8.0_51

ls -l /usr/java/latest
lrwxrwxrwx. 1 root root 21 Jul 21 15:34 /usr/java/latest -> /usr/java/jre1.8.0_51


ls -l /etc/alternatives/java
lrwxrwxrwx. 1 root root 20 Jul 21 17:42 /etc/alternatives/java -> /usr/java/glassfish4

But, now when I run:

java -version
-bash: java: command not found

Environment variables:

env
...
JAVA_HOME=/usr/java/latest
...

So I added the following line to .bashrc:

export PATH="$PATH:$JAVA_HOME"

But still get:

java -version
-bash: java: command not found

Resolved - correct line in bashrc:

export PATH=$PATH:/usr/java/jre1.8.0_51/bin/

I don't know why, but using the environment variable pointing to symbolic link export PATH="$PATH:$JAVA_HOME" does not work, even though it's correctly resolving:

ls -l /usr/java/latest
    lrwxrwxrwx. 1 root root 21 Jul 21 15:34 /usr/java/latest -> /usr/java/jre1.8.0_51

I would really like to understand why?

Answer 1

The reason it didn't work with $JAVA_HOME is that $JAVA_HOME isn't the same thing as $JAVA_HOME/bin. Your binaries (java, javac, javaws, etc) are all found in the bin directory inside your $JAVA_HOME, not in the $JAVA_HOME itself.

The working line in your question points towards /usr/java/jre1.8.0_51/bin; the JAVA_HOME variable points towards /usr/java/latest, which is a symlink to /usr/java/jre1.8.0_51. That's clearly not the same place.

If you use

export PATH="$PATH:$JAVA_HOME/bin"

it will work.