It is shown that a map from
Sp + r to Sp in the image of the J-homomorphism sends particular types of
diffeomorphisms of Sp×Sq into diffeomorphisms of Sp+r×Sq. This is applied to the
problem of determining the diffeomorphism type of an exotic (p + q + 7⋅+ 1)-sphere
obtained by attaching Dp+r+1× lSq to Sp+r× Dq+1 via a diffeomorphism of
Sp + r × Sq.