This is a very basic reproducer for the Spring4Shell (i.e. CVE-2022-22965) vulnerabilty.
The exp.py is taken from https://github.com/craig/SpringCore0day/blob/main/exp.py
Build
mvn package
Deploy
cp target/spring-core-rce-0.0.1-SNAPSHOT.war <tomcat-root>/webapps/ROOT.war
Execute
./exp.py --url http://localhost:8080/