About Doubles

There are three kinds of floating-point numbers (numbers containing a decimal point): floats, doubles, and BigDecimals. Each can be positive or negative. For a description of floats, see Float. For a description of BigDecimals, see BigDecimal.

A double is a 64-bit floating-point primitive number. A double takes up 8 bytes and has 18 places of precision. Doubles are the default floating-point number type. So when you enter a number with a decimal point, the Expression Language treats it as a double.