9.3.3 BIT

The JDBC type BIT represents a single bit value that can be zero or one.
SQL-92 defines an SQL BIT type. However, unlike the JDBC BIT type, this SQL-92 BIT type can be used as a parameterized type to define a fixed-length binary string. Fortunately, SQL-92 also permits the use of the simple non-parameterized BIT type to represent a single binary digit, and this usage corresponds to the JDBC BIT type. Unfortunately, the SQL-92 BIT type is only required in "full" SQL-92 and is currently supported by only a subset of the major databases. Portable code may therefore prefer to use the JDBC SMALLINT type, which is widely supported.
The recommended Java mapping for the JDBC BIT type is as a Java boolean.