Write, in Java, a recursive method countBinaryStrings that has
one integer parameter n and returns the number of binary strings of
length n that do not have two consecutive 0’s. For example, for n =
4, the number of binary strings of length 4 that do not contain two
consecutive 0’s is 8: 1111, 1110, 1101, 1011, 1010, 0111, 0110,
0101. For this problem, your method needs to return only the number
of such strings, not the strings themselves. You...