Above persistence.xml
is missing datasource tag:
<jta-data-source>TestDB-jta-DS</jta-data-source>
Then, for Apache TomEE, data source can be defined in [tomee]/conf/tomee.xml
configuration file. So, proper datasource definition for above persistence.xml would be:
<Resource id="TestDB-jta-DS" type="DataSource">
JdbcDriver com.mysql.jdbc.Driver
JdbcUrl jdbc:mysql://127.0.0.1:3306/TestDB
UserName root
Password 123
JtaManaged true
DefaultAutoCommit false
</Resource>