How do I modify Eclipse code formatting?

In my version of Eclipse, I found the option under Window->Preferences->Java->Code Style->Formatter, then clicked the Edit.. button.

In the new window, go to the Line Wrapping tab and find Method Declarations. You want to change the Line wrapping policy. The Force split check box seems to do the same.

Have a look at Window>Preferences>Java>Code Style>Formatter.

There you can configure almost everything. Your case is found at

Line Wrapping>Method Declarations>Parameters.