Could not open connection caused by This ResultSet is closed

Question

I am trying to make a web app using Maven Spring MVC JPA and Postgres. But I am still not able to persist an object in the database. I have an error while starting a transaction:

org.hibernate.exception.GenericJDBCException: Could not open connection
caused by org.postgresql.util.PSQLException: This ResultSet is closed.

Here is the code

@Controller
public class ExamController {

@GetMapping("/hello")
public String hello(Model model) {

    // EntityManager entityManager = 
EntityManagerUtil.getEntityManager();

    try {
        EntityManager entityManager = 
            Persistence.createEntityManagerFactory("examinatorpu").createEntityManager();

        entityManager.getTransaction().begin();
        entityManager.persist(new Exam());
        entityManager.getTransaction().commit();
        entityManager.close();
        System.out.println("_exam_ok_");

    } catch (Exception e) {
        // entityManager.getTransaction().rollback();
        e.printStackTrace();
        System.out.println("_exam_ko_");
    }

    model.addAttribute("examId", "1");

    return "welcome";
    }
}

Here is my Entity

@Entity
@Table(name = "EXAM")
public class Exam {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "EXAM_ID")
    private long id;

    @Column(name = "TITLE") 
    private String title;

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

}

and here is my persistence.xml

<persistence xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
version="2.0" xmlns="http://java.sun.com/xml/ns/persistence">
<persistence-unit name="examinatorpu"
    transaction-type="RESOURCE_LOCAL">
    <class>examinator.entity.Exam</class>
    <properties>
        <property name="javax.persistence.jdbc.driver" value="org.postgresql.Driver" /> <!-- DB Driver -->
        <property name="javax.persistence.jdbc.url"
            value="jdbc:postgresql://localhost:5432/examinatordb" />
        <property name="javax.persistence.jdbc.user" value="postgres" /> <!-- DB User -->
        <property name="javax.persistence.jdbc.password" value="admin" /> <!-- DB Password -->
        <property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQLDialect" /> <!-- DB Dialect -->
        <property name="hibernate.hbm2ddl.auto" value="update" /> <!-- create / create-drop / update -->
        <property name="hibernate.show_sql" value="true" /> <!-- Show SQL in console -->
        <property name="hibernate.format_sql" value="true" /> <!-- Show SQL formatted -->
        <!-- <property name="hibernate.temp.use_jdbc_metadata_defaults" value="false" 
            /> -->

    </properties>
</persistence-unit>

and here is the error

javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: Could not open connection
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1361)
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1289)
    at org.hibernate.ejb.AbstractEntityManagerImpl.throwPersistenceException(AbstractEntityManagerImpl.java:1371)
    at org.hibernate.ejb.TransactionImpl.begin(TransactionImpl.java:60)
    at examinator.controller.ExamController.hello(ExamController.java:23)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:220)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1457)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)
Caused by: org.hibernate.exception.GenericJDBCException: Could not open connection
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:52)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:304)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:169)
    at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:67)
    at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:160)
    at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1263)
    at org.hibernate.ejb.TransactionImpl.begin(TransactionImpl.java:57)
    ... 40 more
Caused by: org.postgresql.util.PSQLException: This ResultSet is closed.
    at org.postgresql.jdbc2.AbstractJdbc2ResultSet.checkClosed(AbstractJdbc2ResultSet.java:2674)
    at org.postgresql.jdbc2.AbstractJdbc2ResultSet.setFetchSize(AbstractJdbc2ResultSet.java:1791)
    at org.postgresql.jdbc4.Jdbc4Statement.createResultSet(Jdbc4Statement.java:39)
    at org.postgresql.jdbc2.AbstractJdbc2Statement$StatementResultHandler.handleResultRows(AbstractJdbc2Statement.java:211)
    at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1772)
    at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257)
    at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:500)
    at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:374)
    at org.postgresql.jdbc2.AbstractJdbc2Connection.execSQLUpdate(AbstractJdbc2Connection.java:263)
    at org.postgresql.jdbc2.AbstractJdbc2Connection.getTransactionIsolation(AbstractJdbc2Connection.java:775)
    at org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.getConnection(DriverManagerConnectionProviderImpl.java:182)
    at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:276)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:297)
    ... 45 more

Answer 1

I just changed the version of the JDBC to the latest one and now it works fine!

<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>9.4-1200-jdbc41</version>
</dependency>

Answer 2

you need to update your postgres jdbc driver just as Judy1989 said.

this one

<dependency>
        <groupId>org.postgresql</groupId>
        <artifactId>postgresql</artifactId>
        <version>9.4-1200-jdbc41</version>
    </dependency>

is worked for me too. thanks guys!