I am encountering multiple memory leaks in my multi-module Maven project, and I am unable to identify the root cause despite extensive debugging. I have tried using tools like SonarQube, PMD, CheckStyle, and SpotBugs, but nothing has resolved the issue.

Here is an overview of my environment:

• Java version: 17
• Tomcat version: 10
• JNDI data source: Managed by Tomcat
• MySQL driver: mysql-connector-j-9.1.0 (available only in Tomcat's lib folder, not in Maven POM files)
• Spring framework version: 6.2.0
• Spring Security version: 6.2.3
• Hibernate version: 6.2.0.Final
• Hibernate Commons: 7.0.1.Final

Here is the relevant configuration:

HikariCP data source configuration:

<bean id="dataSource" class="com.zaxxer.hikari.HikariDataSource" destroy-method="close">
    <property name="dataSourceJNDI" value="java:/comp/env/jdbc/xxx" />  
    <property name="maximumPoolSize" value="10" />
    <property name="minimumIdle" value="10" />   
    <property name="idleTimeout" value="300000" />   
    <property name="connectionTestQuery" value="SELECT 1" />
    <property name="leakDetectionThreshold" value="30000" />
    <property name="autoCommit" value="true" />
</bean>

EntityManager configuration:

<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="persistenceUnitName" value="xxxxx" />
    <property name="dataSource" ref="dataSource" />
    <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
            <property name="generateDdl" value="false" />
        </bean>
    </property>
    <property name="jpaPropertyMap">
        <map>
            <entry key="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
            <entry key="hibernate.enable_lazy_load_no_trans" value="true" />
            <entry key="hibernate.jdbc.batch_size" value="50" />
        </map>
    </property>
</bean>

JNDI resource configuration in Tomcat:

<Resource name="jdbc/MainDB" auth="Container"
          type="javax.sql.DataSource" username="rrrrr" password="ttttt"
          driverClassName="com.mysql.cj.jdbc.Driver"
          url="jdbc:mysql://xxxxx/yyyyy?useSSL=false&amp;dontTrackOpenResources=true"
          maxIdle="4" maxTotal="2000" minIdle="2"
          testOnBorrow="true" validationQuery="SELECT 1" 
          removeAbandonedOnBorrow="true" removeAbandonedTimeout="600"
          logAbandoned="true" />

Abstract DAO implementation (GenericDaoImpl):

@PersistenceContext
protected EntityManager entityManager;

I am not directly managing sessions or connections, as everything is delegated to Tomcat, Hibernate, and Spring. Despite configuring HikariCP and using JNDI for connection pooling, I continue to see memory leak issues.

I suspect that the problem might be related to either:

• Tomcat's handling of the MySQL driver.
• Hibernate's lazy loading or batch processing configuration.

I have enabled Hibernate's generate_statistics and show_sql options but have not identified anything unusual.

Could someone help me troubleshoot this issue or provide guidance on common pitfalls that might cause memory leaks in a similar setup? Any tools, techniques, or configurations I might have overlooked would also be greatly appreciated.