Concurrent testing with TestNG and Spring Transaction

Question

I have a service class, the service class is annotated with @Transactional(propagation = Propagation.REQUIRES_NEW) and its public method is defined in an interface:

public interface UniqueKeyGeneratorService {
    void initializeUniqueKeys(Entity entity);
}

@Transactional(propagation = Propagation.REQUIRES_NEW)
public final class KeyGeneratorServiceImpl implements UniqueKeyGeneratorService, DisposableBean {

    private final UniqueKeyGeneratorStrategy strategy;

    private KeyGeneratorServiceImpl(final UniqueKeyGeneratorStrategy strategy) {
        this.strategy = strategy;
    }

    @Override
    public void initializeUniqueKeys(final Entity entity) {
        // ... the business logic
    }

    // ... some private methods

    @Override
    public void destroy() {
        strategy.destroy();
    }
}

And the bean is created using a FactoryBean (to initialize the strategy).

I want to test the service, so I configured an embedded H2 database, defined a connection pool using Apache Commons DBCP and write proper test code as:

@ContextConfiguration("/path/to/xml/config/file.xml")
@Transactional
public class TestUniqueKeyGeneratorService extends AbstractTransactionalTestNGSpringContextTests {

    @Autowired
    private UniqueKeyGeneratorService service;

    @Test
    @Rollback(false)
    public void testCodeGeneration() {
        final Department department1 = new Department();
        department1.setName("Abcd");
        service.initializeUniqueKeys(department1);
        final String code = department1.getCode();

        Assert.assertNotNull(code);
    }

    // ... some more test methods
}

and have

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
                           http://www.springframework.org/schema/context
                           http://www.springframework.org/schema/context/spring-context-3.0.xsd
                           http://www.springframework.org/schema/tx
                           http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">

  <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
    <property name="driverClassName" value="org.h2.Driver"/>
    <property name="url" value="jdbc:h2:mem:db1"/>
    <property name="username" value="sa"/>
    <property name="password" value=""/>
  </bean>

  <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    <property name="dataSource" ref="dataSource"/>
  </bean>

  <tx:annotation-driven/>

  <bean id="uniqueKeyGeneratorService"
    class="com.mycompany.uniquekey.UniqueKeyGeneratorServiceFactoryBean">
    <property name="dataSource" ref="dataSource"/>
  </bean>

</beans>

the test passes, but when I change the @Test annotation to @Test(invocationCount = 10, singleThreaded = false, threadPoolSize = 2) following exception occures:

org.springframework.transaction.CannotCreateTransactionException: Could not open JDBC Connection for transaction; nested exception is java.sql.SQLException: Connection is closed.
    at org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:240) ~[org.springframework.jdbc-3.1.3.RELEASE.jar:3.1.3.RELEASE]
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:371) ~[org.springframework.transaction-3.1.3.RELEASE.jar:3.1.3.RELEASE]
    at org.springframework.test.context.transaction.TransactionalTestExecutionListener$TransactionContext.startTransaction(TransactionalTestExecutionListener.java:514) ~[org.springframework.test-3.1.3.RELEASE.jar:3.1.3.RELEASE]
    at org.springframework.test.context.transaction.TransactionalTestExecutionListener.startNewTransaction(TransactionalTestExecutionListener.java:272) ~[org.springframework.test-3.1.3.RELEASE.jar:3.1.3.RELEASE]
    at org.springframework.test.context.transaction.TransactionalTestExecutionListener.beforeTestMethod(TransactionalTestExecutionListener.java:165) ~[org.springframework.test-3.1.3.RELEASE.jar:3.1.3.RELEASE]
    at org.springframework.test.context.TestContextManager.beforeTestMethod(TestContextManager.java:358) ~[org.springframework.test-3.1.3.RELEASE.jar:3.1.3.RELEASE]
    at org.springframework.test.context.testng.AbstractTestNGSpringContextTests.springTestContextBeforeTestMethod(AbstractTestNGSpringContextTests.java:146) [org.springframework.test-3.1.3.RELEASE.jar:3.1.3.RELEASE]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.6.0_31]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) ~[na:1.6.0_31]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) ~[na:1.6.0_31]
    at java.lang.reflect.Method.invoke(Method.java:597) ~[na:1.6.0_31]
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:80) [org.testng-6.8.jar:6.8-201210030754]
    at org.testng.internal.Invoker.invokeConfigurationMethod(Invoker.java:564) [org.testng-6.8.jar:6.8-201210030754]
    at org.testng.internal.Invoker.invokeConfigurations(Invoker.java:213) [org.testng-6.8.jar:6.8-201210030754]
    at org.testng.internal.Invoker.invokeMethod(Invoker.java:653) [org.testng-6.8.jar:6.8-201210030754]
    at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:901) [org.testng-6.8.jar:6.8-201210030754]
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1231) [org.testng-6.8.jar:6.8-201210030754]
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:127) [org.testng-6.8.jar:6.8-201210030754]
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:111) [org.testng-6.8.jar:6.8-201210030754]
    at org.testng.internal.thread.ThreadUtil$2.call(ThreadUtil.java:64) [org.testng-6.8.jar:6.8-201210030754]
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) [na:1.6.0_31]
    at java.util.concurrent.FutureTask.run(FutureTask.java:138) [na:1.6.0_31]
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) [na:1.6.0_31]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) [na:1.6.0_31]
    at java.lang.Thread.run(Thread.java:662) [na:1.6.0_31]
Caused by: java.sql.SQLException: Connection is closed.
    at org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.checkOpen(PoolingDataSource.java:185) ~[org.apache.commons-dbcp-1.4.jar:1.4]
    at org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.getAutoCommit(PoolingDataSource.java:234) ~[org.apache.commons-dbcp-1.4.jar:1.4]
    at org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:218) ~[org.springframework.jdbc-3.1.3.RELEASE.jar:3.1.3.RELEASE]
    ... 24 common frames omitted

any idea how to handle this exception?

p.s. I reviewed H2 documentations, and it supports multiple connections in embedded mode.

Answer 1

The answer is located in TestNG multithreaded test with Spring @Transactional