question: private void validateExplicitHashKey ( final String explicitHashKey ) { if ( explicitHashKey == null ) { return ; } BigInteger b = null ; try { b = new BigInteger ( explicitHashKey ) ; if ( b . compareTo ( UINT_128_MAX ) > 0 || b . compareTo ( BigInteger . ZERO ) < 0 ) { throw new IllegalArgumentException ( "Invalid explicitHashKey, must be greater or equal to zero and less than or equal to (2^128 - 1), got " + explicitHashKey ) ; } } catch ( NumberFormatException e ) { throw new IllegalArgumentException ( "Invalid explicitHashKey, must be an integer, got " + explicitHashKey ) ; } }
target:  Validate the explicit hash key of an input Kinesis user record.