private static boolean isFieldPresent(short bitMask, int fieldBitMask) {
        return (bitMask & fieldBitMask) != 0;
    }
Returns {@code true} if the given {@code bitMask} argument indicates that the specified field has been
serialized and therefore should be read during deserialization, {@code false} otherwise.

@param bitMask      the aggregate bitmask for all fields that have been serialized.  Individual bits represent
                    the fields that have been serialized.  A bit set to 1 means that corresponding field has
                    been serialized, 0 means it hasn't been serialized.
@param fieldBitMask the field bit mask constant identifying which bit to inspect (corresponds to a class attribute).
@return {@code true} if the given {@code bitMask} argument indicates that the specified field has been
serialized and therefore should be read during deserialization, {@code false} otherwise.
@since 1.0
core/src/main/java/org/apache/shiro/session/mgt/SimpleSession.java