With the update to tomcat 9.0.81 (due to the released CVE) we run into an IllegalArgumentException.

Looking at the previous implementation before (9.0.80), it seems like some refactoring issue. I hope i chose the right project/component and I didnt find a similar bug report yet.

Previous implementation did 
Proxy.getProxyClass(ConnectionPool.class.getClassLoader(), new Class[] {java.sql.Connection.class,javax.sql.PooledConnection.class});

New implementation is 
Proxy.getProxyClass(ConnectionPool.class.getClassLoader(), new Class[] {Connection.class,PooledConnection.class});
-> Connection has import to java.sql.Connection.class and works as before.
-> PooledConnection has no import and now resolves to org.apache.tomcat.jdbc.pool.PooledConnection and leads to the IllegalArgumentException (was javax.sql.PooledConnection previous).


Stacktrace:
Caused by: java.sql.SQLException
	at org.apache.tomcat.jdbc.pool.ConnectionPool.setupConnection(ConnectionPool.java:351)
	at org.apache.tomcat.jdbc.pool.ConnectionPool.getConnection(ConnectionPool.java:200)
	at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:133)
	at customer.Database.getConnection(Database.java:67)
	... 43 more
Caused by: java.lang.IllegalArgumentException: org.apache.tomcat.jdbc.pool.PooledConnection is not an interface
	at java.base/java.lang.reflect.Proxy$ProxyBuilder.validateProxyInterfaces(Proxy.java:691)
	at java.base/java.lang.reflect.Proxy$ProxyBuilder.<init>(Proxy.java:630)
	at java.base/java.lang.reflect.Proxy.lambda$getProxyConstructor$1(Proxy.java:428)
	at java.base/jdk.internal.loader.AbstractClassLoaderValue$Memoizer.get(AbstractClassLoaderValue.java:329)
	at java.base/jdk.internal.loader.AbstractClassLoaderValue.computeIfAbsent(AbstractClassLoaderValue.java:205)
	at java.base/java.lang.reflect.Proxy.getProxyConstructor(Proxy.java:426)
	at java.base/java.lang.reflect.Proxy.getProxyClass(Proxy.java:386)
	at org.apache.tomcat.jdbc.pool.ConnectionPool.getProxyConstructor(ConnectionPool.java:370)
	at org.apache.tomcat.jdbc.pool.ConnectionPool.setupConnection(ConnectionPool.java:339)