@Entity public class Foo{
@Id int id;
boolean bar;
[..]
}

SELECT id,bar FROM Foo f

public class CustomHSQLDialect extends org.hibernate.dialect.HSQLDialect
{
    public CustomHSQLDialect()
    {
        registerColumnType(Types.BOOLEAN, "boolean");
        registerHibernateType(Types.BOOLEAN, "boolean");
    }
}

public class HSQLDialect_HHH_1598 extends org.hibernate.dialect.HSQLDialect {

    public HSQLDialect_HHH_1598() {
        super();
        registerColumnType(Types.BIT, "boolean");

        // Assert that the new type is registered correctly.
        if (!"boolean".equals(getTypeName(Types.BIT))) {
            throw new IllegalStateException("Failed to register HSQLDialect "
                    + "column type for Types.BIT to \"boolean\".");
        }
    }
}