How to select/copy current line without using mouse in IntelliJ IDEA

CTRL + X CTRL + V

CTRL + D - duplicate line CTRL + Y - delete line

If you have nothing selected, I think you can just hit CTRL-C to copy a line (or CTRL-X to cut it)...

http://grahamhackingscala.blogspot.co.uk/2010/08/fast-quick-line-cut-copy-intellij-idea.html

Hope this helps.