The setOneTouchExpandable() API allows user to expand/collapse the divider using
single mouse click.

It is necessary to have that fuctionality available programatically also.
Something like -

1. setDividerLocation(MINIMUM_LOCATION);
2. setDividerLocation(DEFAULT_LOCATION);
3. setDividerLocation(MAXIMUM_LOCATION);

I know that no. 1 can be achieved with setDividerLocation(0);
I know that no. 1 can be achieved with resetToPreferredSizes();, but this
may not track the changes in the size of JSplitPane.
No. 3 is not possible easily.