On my linux box, after typing `which java`, I get

> 
> /usr/bin/java
> 
> 
> 

After typing `whereis java`, I get

> 
> java: /usr/bin/java /etc/java /usr/share/java /usr/share/man/man1/java.1.gz
> 
> 
> 

What are the meanings of these two results? When setting up the JAVA\_HOME, which one should I use?