java.sql.SQLException: Field 'supplier_id' doesn't have a default value
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:946)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2985)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1631)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1723)
    at com.mysql.jdbc.Connection.execSQL(Connection.java:3277)
    at com.mysql.jdbc.Statement.executeUpdate(Statement.java:1402)
    at com.mysql.jdbc.Statement.executeUpdate(Statement.java:1317)

ALTER TABLE `xxx` ALTER `supplier_id` SET DEFAULT NULL

ALTER TABLE `xxx` CHANGE `supplier_id` `supplier_id` INT(10)AUTO_INCREMENT PRIMARY KEY;

<property name="hbm2ddl.auto">create</property>.