Hello Neeraj,
it depends on what kind of LAF you use. If you use the
Java LAF, then it is easy. For this LAF, you can create themes. A theme consists of 6 colors and 6 fonts.
So you could write your own theme or you extend from the DefaultTheme and you can overwrite the color, which ontains the color for the divider.
The only problem is, you will change lots of other component colors too.
Another idea would be to go directly over JSplitPane.getUI(), which returns u a SplitPaneUI, which you probably can cast to a BasicSplitPaneUI. There you will find a function getDivider() and this is a Component, where you can set any Color.
Hope that helps
Rene