I though it was float

Question

what's double

Answer 1

double can have much larger numbers than float. Don't use it unless you actually need it. Both are numbers with/without a decimal point

Answer 2

Double > Float
By default decimal numbers are of type double in Java.
So : float a = 1.5;
Will give an error, unless you cast the double to a float someway.
Like:
float a = 1.5f;

Answer 3

float double is datatype