When creating a new Datasource on Weblogic 12.1.3 to MySQL 8.0.15, I got this error:
Unable to load authentication plugin 'caching_sha2_password'.
com.mysql.jdbc.SQLError.createSQLException(SQLError.java:910)
A quick search found this question, and the solution is to switch the password encryption back to the approach used in prior MySQL versions with:
ALTER USER 'youruserid'@'localhost' IDENTIFIED WITH mysql_native_password BY 'newpassword';