How to convert a single MySql table to utf8mb4 (from latin1) MySql version 5.6.39

i have one table that now needs to support chinese characters. the other tables in the database do not need utf8mb4 encoding.  

what have i done thus far:
1) backed up database!
2) alter table &lt;blah&gt; default character set utf8mb4 collate utf8mb4_unicode_ci;
3) alter table &lt;blah&gt; convert to character set utf8mb4 collate utf8mb4_unicode_ci;
4) (for all columns except numeric) alter table &lt;blah&gt; change col1 col1 varchar(xx) character set utf8mb4 collate utf8mb4_unicode_ci;  

what i have not done thus far:
1) alter database &lt;blahDB&gt; character set utf8mb4 collate utf8mb4_unicode_ci;

i've seen several questions/answers here...notibly:
How to easily convert utf8 tables to utf8mb4 in MySQL 5.5  Is it necessary to alter the database when all i want is for one table within it to be utf8mb4? 

Right now, when i insert a "special" (unicode) char (0x2015) in the middle of a string into the table, it is stored as '?'. Help!!
Going by what you have to do within a PHP-Webserver environment to use utf8 / utf8mb4, you have up to 5 or more construction places. And you covered 2 of them 


collation of table and column(s)
overwork existing string-data in said columns 


leaves:


make sure your application / tool uses the correct collation as well
make sure you communicate with the database using the correct collation
set the frontend of your application / tool to handle said collation 


As JAVA is well prepared I guess its the database connection ...