Regex for validating only numbers and dots

Question

I want a java regex expression that accepts only the numbers and dots.

for example,

             1.1.1 ----valid
             1.1   ----valid
              


        

Answer 1

"^\\d(\\.\\d)*$"

1     ----valid (if it must be not valid, replace `*` => `+` )
1.1.1 ----valid
1.1   ----valid
1.1.1.1---valid
1.    ----not valid
11.1.1 ---not valid (if it must be valid, add `+` after each `d`)