Tomcat jdbc pool shows ClassNotFoundException but works

Question

To configure a JDBC pool for Microsoft SQLServer in Tomcat 9 I've added below to server.xml

<Resource auth="Container" 
   type="javax.sql.DataSource" driverClassName="com.microsoft.sqlserver.jdbc.SQLServerDriver" 
   factory="org.apache.tomcat.jdbc.pool.DataSourceFactory" jdbcInterceptors="org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer" 
   maxActive="100" maxIdle="30"  maxWait="10000" name="jdbc/SABA" 
   defaultAutoCommit="true" 
   username="user" password="pass" url="jdbc:sqlserver://myserver:1433;DatabaseName=mydb;" />

During tomcat startup I get lots of ClassNotFoundException

Caused by: java.lang.ClassNotFoundException: com.microsoft.sqlserver.jdbc.SQLServerDriver

This is obviously normal as I did not copy the SQL Server drivers into Tomcat libs, but after application startup, the pool is working and I can get connection from it. I have the SQL Server drivers in my application WEB-INF\lib.

Is it a default behavior? If this is normal, can I suppress the exception during Tomcat startup?