9.3.11 FLOAT

The JDBC type FLOAT is basically equivalent to the JDBC type DOUBLE. We provided both FLOAT and DOUBLE in a possibly misguided attempt at consistency with previous database APIs. FLOAT represents a "double precision" floating point number that supports 15 digits of mantissa.
The corresponding SQL type FLOAT is defined in SQL-92. The SQL-92 standard leaves the precision of FLOAT up to the implementation, but in practice all the major databases supporting FLOAT support a mantissa precision of at least 15 digits.
The recommended Java mapping for the FLOAT type is as a Java double. However, because of the potential confusion between the double precision SQL FLOAT and the single precision Java float, we recommend that JDBC programmers should normally use the JDBC DOUBLE type in preference to FLOAT.