How to set JAVA_HOME path on Ubuntu?

How can I setup `JAVA_HOME` path without having to set it each time I restart my machine? I've used the following ways when trying to set JAVA_HOME on my Ubuntu machine: 1) From terminal I've executed the following command: export JAVA_HOME=/usr/lib/jvm/jdk1.7.0 2) I've edited the `/etc/enviroment` file directly to add `JAVA_HOME` path in it What's really strange is that if I test `JAVA_HOME` using the `echo` command after an of the above two ways, I can see it is set correctly, but if I restart, logout/ login again or even after working on the machine for a while the `JAVA_HOME` is no more set and I have to set it again using any of the above two ways. So can someone please tell me what I am doing wrong here?