INFORMATION_SCHEMA.COLUMNS table lists nullable columns as non-nullable

1. create hive table ( these columns are nullable)
hive> DROP TABLE IF EXISTS STUDENTS;
CREATE EXTERNAL TABLE STUDENTS
(
ID VARCHAR(24),
NAME VARCHAR(24),
STREET VARCHAR(256),
ZIPCODE INT,
STATE VARCHAR(20)
)
ROW FORMAT DELIMITED FIELDS
TERMINATED BY ','
STORED AS TEXTFILE LOCATION "/drill/testdata/information-schema/students/";

2. From drill issue the below query and check the 'IS_NULLABLE" column

SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA='hive' AND TABLE_NAME='students';