Metaspace OOM after repeated hot deployment of Spring Boot war file in Tomcat

Question

I create a very simple SpringBoot Application accessing Oracle database with one table by JPA. I create a war file and repeatedly deploy and undeploy in a tomcat server. After serveral times there is MetaSpace OOM.

Environment: a. OS : Ubuntu 22.04.3
b. JVM : Oracle Java 11.0.18 and Oracle java 17.0.17 (tested both)
c. Tomcat : 9.0.75
d. SpringBoot : 2.7.5
e. Oracle : version 19c
f. Oracle jdbc : com.oracle.database.jdbc:ojdbc11:23.2.0.0\

Source code:

Policy.java:

Getter
@Setter
@Entity


@Table(name = "policy_m")
public class Policy {


   @Column(name = "policy_agreement_id")
   private Long policyAgreementId;
   @Id
   @Column(name = "policy_num")
   private String policyNum;
  
}

PolicyRepository.java:

@Repository
public interface PolicyRepository extends JpaRepository<Policy, String> {


   @Query(value = "select * from policy_m where policy_num = :policyNum", nativeQuery = true)
   Policy getPolicyByPolicyNum(@Param("policyNum") String policyNum);


}

PolicyServiceImpl.java:

@Service
public class PolicyServiceImpl implements PolicyService {


   @Autowired
   private PolicyRepository policyRepository;


   public Policy getPolicyByPolicyNum(String policyNum) {
       return policyRepository.getPolicyByPolicyNum(policyNum);
   }
}

DemoController.java:

@RestController
public class DemoController {

   @Autowired
   private PolicyService policyService;

   @GetMapping("/{policyNum}")
   public Policy database(@PathVariable("policyNum") String policyNum) {
       return policyService.getPolicyByPolicyNum(policyNum);
   }
}

Steps to reproduce:

1. prepare the war file
2. deploy to the tomcat through the admin console
3. undeploy the application through the admin console
4. repeat step 2 - 3 until it throws MetaSpace OOM

The VisualVM shows the chart as attached

At the plateau at the right hand side, the tomcat actually already hanged.