You will need extra configuration if you want an auto generated varchar.
The generation of DDL is translating to:
CREATE TABLE employee (EMP_ID VARCHAR(255) AUTO_INCREMENT NOT NULL, FIRST_NAME VARCHAR(255), LAST_NAME VARCHAR(255), PRIMARY KEY (EMP_ID))
and the log is saying:
Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Incorrect column specifier for column 'EMP_ID'
Error Code: 1063
MySql is rejecting EMP_ID becuase it cant have AUTO_INCREMENT with varchar, and you need to specify the auto generation for it. Probably Derby has this feature, and it works different for MySql.
You might wanna look in this answer.
Or just change the type of EMP_ID to an integer number if you dont mind the type or for a quick test.