In eclipse 4.2, I can just type:
joptionpane
and press CTRL+SPACE and it will turn into:
<
You can disable the case sensitivity of the code completion in the settings menu:
File -> Settings -> Editor -> Code completion -> Case sensitive completion
If you then type "jo" and hit TAB, it will expand to JOptionPane.
IDEA is very senstive to capitalisation so I doubt ti will ignore it. You can type JOP+<tab>
and it will give you JOptionPane.