Mysql 5.7 Issue in declare handler for duplicate key - mysql

Question

We are facing an issue in declaring handlers in MYSQL 5.7 stored procedure.
Using the documentation present in https://dev.mysql.com/doc/refman/5.7/en/get-diagnostics.html, I'm trying to create handler in my stored procedure to do the following:
If a duplicate key appears, log it and move on insert good row.
End of the stored proc, get me all the error and success rows inserted.
As you can see below, we don't have primary key for table, however have the unique key constraint.
Input
CALL userTableInsert('{"userid":100, "username":"Hello"}, {"userid":102, "username":"World"}, {"userid":102, "username":"World"}', #got_dups)
Expected Output
100:Hello should get inserted and 102:World should get errored out and status needs to be corrected depicted in the output of the stored procedure.
Getting ERR : Error Code: 1064. You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DECLARE CONTINUE HANDLER FOR SQLEXCEPTION ...'
Table: user_table
CREATE TABLE `user_table` (
user_id int(20) NOT NULL,
user_name varchar(255) DEFAULT NULL,
created_by varchar(255) NOT NULL,
created_date date NOT NULL,
UNIQUE KEY `user_ukey` (user_id, user_name)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
===============================================
Stored Procedure
===============================================
DELIMITER $$
DROP PROCEDURE IF EXISTS schema.userTableInsert$$
CREATE PROCEDURE schema.userTableInsert(IN JSONArrayParam MEDIUMTEXT, OUT
got_dups INT)
SQL SECURITY INVOKER
BEGIN
DECLARE code CHAR(5) DEFAULT '00000';
DECLARE msg TEXT;
DECLARE rows INT;
DECLARE result TEXT;
DECLARE rowsJSON MEDIUMTEXT DEFAULT NULL;
SET rowsJSON = TRIM(JSONArrayParam);
SET rowsJSON = TRIM(LEADING '[' FROM rowsJSON);
SET rowsJSON = TRIM(TRAILING ']' FROM rowsJSON);
DROP TEMPORARY TABLE IF EXISTS rowsToUse;
CREATE TEMPORARY TABLE rowsToUse (
user_id INT NOT NULL,
user_name VARCHAR(255) DEFAULT NULL
) ENGINE=MEMORY;
WHILE (rowsJSON != '') DO
BEGIN
DECLARE rowJSON VARCHAR(4096) DEFAULT NULL;
DECLARE temp JSON;
DECLARE userid INT DEFAULT NULL;
DECLARE username VARCHAR(255) DEFAULT NULL;
SET rowJSON = CONCAT(SUBSTRING_INDEX(rowsJSON, '}', 1), '}');
SET temp = JSON_EXTRACT(rowJSON, '$.userid');
SET userid = COALESCE(IF(JSON_TYPE(temp) = 'NULL', NULL, REPLACE(temp, '\"', '')));
SET temp = JSON_EXTRACT(rowJSON, '$.username');
SET username = COALESCE(IF(JSON_TYPE(temp) = 'NULL', NULL, REPLACE(temp, '\"', '')));
INSERT INTO rowsToUse(user_id, user_name)
VALUES(userid, username);
IF LOCATE('{', rowsJSON, 2) > 0 THEN
SET rowsJSON = SUBSTRING(rowsJSON, LOCATE('{', rowsJSON, 2));
ELSE
SET rowsJSON = '';
END IF;
END;
END WHILE;
SET SQL_SAFE_UPDATES=0;
# Getting syntax error here
DECLARE CONTINUE HANDLER FOR 1062
BEGIN
GET DIAGNOSTICS CONDITION 1
code = RETURNED_SQLSTATE, msg = MESSAGE_TEXT;
END;
INSERT INTO user_table(user_id, user_name, created_by , created_date)
SELECT user_id, user_name, 'system', NOW()
FROM rowsToUse;
IF code = '00000' THEN
GET DIAGNOSTICS rows = ROW_COUNT;
SET result = CONCAT('insert succeeded, row count = ',rows);
ELSE
SET result = CONCAT('insert failed, error = ',code,', message = ',msg);
END IF;
DROP TEMPORARY TABLE IF EXISTS rowsToUse;
SET SQL_SAFE_UPDATES=1;
SELECT result;
END
$$
DELIMITER ;
==============================================================
Kindly help me on this.