double « Java Source And Data Type « SCJP

1.14.1.Attach a D or d to double literals, but it is not necessary.
1.14.2.NaN values indicates that a calculation has no result in ordinary arithmetic
1.14.3.A value containing a decimal point is assumed to be the 64-bit double,
1.14.4.Division by zero in floating-point-arithmetic: No exception occurs;
1.14.5.See if a floating-point result is NaN, use the Float.isNaN or Double.isNaN static method.
1.14.6.Float and Double classes define MAX_VALUE, MIN_VALUE, POSITIVE_INFINITY, and NEGATIVE_INFINITY.