To prepare juice : Combine currant juice and fruit in a flat pan; add 4 cups sugar; and cook 5 minutes.
Let stand 12 hours or overnight in a cool place.
Add remaining sugar.
Bring slowly to a boil, stirring until sugar dissolves.
Cook rapidly almost to jellying point, about 30 minutes.
Stir occasionally to prevent sticking.
Pour hot into hot jars, leaving 1/4-inch head space.
Process 15 minutes in boiling water bath