"which java" in CentOS prints wrong java path

Question

I am not sure why "which java" and "whereis java" paths are not correct. I tried to edit ~/.bash_profile and /etc/environment but did not help. The desired path is what is seen in "echo $JAVA_HOME" below but the same is not reflected in "which java"

Below is what I get in CentOS 6.4:

which java

/usr/bin/java

---

java -version

java version "1.7.0_45"

JAVA(TM) SE Runtime Environment (build 1.7.0_45-b18)

JAVA HotSpot (TM) 64-bit Server VM (build 24.45-b08, mixed mode)

---

whereis java

java: /usr/bin/java /etc/java /usr/lib/java /usr/share/java

---

echo $JAVA_HOME

/usr/java/jdk1.7.0_45/jre => desired shows correct when echo $JAVA_HOME

---

Answer 1

Run alternatives --config java to pick the Java version you want to use as default. It will print out a list of installed Javas to choose from.

which java, however, will always print out /usr/bin/java. This doesn't mean it's set wrong! Observe:

$ ls -l `which java`
lrwxrwxrwx 1 root root 22 Oct 19 11:49 /usr/bin/java -> /etc/alternatives/java
$ ls -l /etc/alternatives/java
lrwxrwxrwx 1 root root 35 Oct 19 11:49 /etc/alternatives/java -> /usr/lib/jvm/jre-1.5.0-gcj/bin/java

If you use alternatives to change the path to IcedTea, ls -l /etc/alternatives/java will reflect that.

Answer 2

Your PATH (and nothing else) determines which directories to look for commands. This is the same in Linux, Solaris, and DOS.

When you do a which {command} it find the first directory you can execute the command in.

When you update your PATH in .bashrc, you have to source it again to change your current settings.