question: @ Parameterized . Parameters public static Collection < Object [ ] > configs ( ) { return Arrays . asList ( new Object [ ] [ ] { { "inner" , "on" , "v2" , true } , { "left" , "on" , "v1" , true } , { "left" , "on" , "v2" , true } } ) ; }
target:  return all config combinations, where first setting specifies join type (inner or left), and the second setting specifies whether to force using coprocessors(on, off or unset).