Disclaimer

Even if I googled, only English was a hit, so it is a memo writing level record.

Premise

--Database is Oracle --The server you are currently using is Tomcat 7 or lower --The JDBC driver you are using now is ojdbc6.jar

Thing you want to do

I want to upgrade Tomcat from 7 to 8.5 or 9.0

Error message

java.lang.AbstractMethodError: oracle.jdbc.driver.T4CConnection.getSchema()Ljava/lang/String;

Cause

--Java 7 or higher is required from Tomcat 8. --In Java 7, the getSchema () method has been added to the Connection class, and it is used by Tomcat's connection pool (dbcp2). --The jdbc driver for Java 7 is ojdbc7.jar

Correspondence

Throw ojdbc7.jar (or the latest jdbc driver) into the tomcat lib folder