Servlet dispatcher threw exception , Spring 4.1.5 on Tomcat 7 (JBoss EWS 2.0) (Openshift)

Question

I'm developping a small spring web-mvc application for practice. I've deployed it on Tomcat 7 (at Openshift.com) . I use a MySql 5.5 database too and work in IntelliJ. The problem begins when the DAO class should be loaded. Servlet.init() for servlet dispatcher throws a following exeption:

javax.servlet.ServletException: Servlet.init() for servlet dispatcher threw exception
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:683)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
    org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.lang.Thread.run(Thread.java:745)

root cause

org.springframework.beans.factory.CannotLoadBeanClassException: Error loading class [pf.repository.JdbcPhotoDao] for bean with name 'jdbcPhotoDao' defined in ServletContext resource [/WEB-INF/dispatcher-servlet.xml]: problem with class file or dependent class; nested exception is java.lang.UnsupportedClassVersionError: pf/repository/JdbcPhotoDao : Unsupported major.minor version 52.0 (unable to load class pf.repository.JdbcPhotoDao)
    org.springframework.beans.factory.support.AbstractBeanFactory.resolveBeanClass(AbstractBeanFactory.java:1331)
    org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineTargetType(AbstractAutowireCapableBeanFactory.java:622)
    org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.predictBeanType(AbstractAutowireCapableBeanFactory.java:591)
    org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1397)
    org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:968)
    org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:735)
    org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
    org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
    org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:663)
    org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:629)
    org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:677)
    org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:548)
    org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:489)
    org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
    javax.servlet.GenericServlet.init(GenericServlet.java:158)
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:683)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
    org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.lang.Thread.run(Thread.java:745)

In my mind , it's a thing in my DAO implementation "JdbcPhotoDao" but I have not idea what is it. I tried to change the project bytecode version in IntelliJ Settings -> Build, Execution, Deployement -> Compiler -> Java compiler for 1.6 because I use JDK 1.8 but that doesn't solve my issue. Here's the code of JdbcPhotoDao.java

package pf.repository;

import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.*;
import pf.domain.Photo;

public class JdbcPhotoDao implements PhotoDao {

    JdbcTemplate jdbct;

    public void setJdbct(JdbcTemplate jdbct) {
        this.jdbct = jdbct;
    }

    @Override
    public List<Photo> getPhotosList() {
        List<Photo> photoslist = jdbct.query("select ID,LINK,GALLERYID from PHOTOS",
                new RowMapper<Photo>() {
            @Override
            public Photo mapRow(ResultSet rs, int rowNum) throws SQLException {
                Photo result = new Photo();
                result.setId(rs.getInt("ID"));
                result.setLink(rs.getString("LINK"));
                result.setGalleryId(rs.getInt("GALLERYID"));
                return result;
            }
        });

        return photoslist;
    }


}

The web.xml and application context

web.xml

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="2.4"
         xmlns="http://java.sun.com/xml/ns/j2ee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
         http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" >

    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>*.htm</url-pattern>
    </servlet-mapping>

    <welcome-file-list>
        <welcome-file>
            index.jsp
        </welcome-file>
    </welcome-file-list>


</web-app>

dispatcher-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
       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.xsd">

    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"></property>
        <property name="prefix" value="/WEB-INF/jsp/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>

    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="${jdbc.driverClassName}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>

    <bean id="propertyConfigurer"
          class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <list>
                <value>classpath:jdbc1.properties</value>
            </list>
        </property>
    </bean>

    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"/>
    </bean>

    <bean id="jdbcPhotoDao" class="pf.repository.JdbcPhotoDao">
        <property name="jdbct" ref="jdbcTemplate"/>
    </bean>

    <bean id="photoService" class="pf.service.SimplePhotoService">
        <property name="photodao" ref="jdbcPhotoDao"/>
    </bean>

    <bean name="/gallery.htm" class="pf.web.GalleryController">
        <property name="photoservice" ref="photoService"/>
    </bean>

I'll be very indebted for some tips which could help me with this problem

Answer 1

Since you are building with Gradle, try setting you JAVA_HOME to 1.6 and build and deploy.

Answer 2

Probably you are compiling with Java 8 and is running the application on Java 7 JVM or any older version:

JDK 1.0 -> major version 45 and minor version 3
JDK 1.1 -> major version 45 and minor version 3
JDK 1.2 -> major version 46 and minor version 0
JDK 1.3 -> major version 47 and minor version 0
JDK 1.4 -> major version 48 and minor version 0
JDK 1.5 -> major version 49 and minor version 0
JDK 1.6 -> major version 50 and minor version 0
JDK 1.7 -> major version 51 and minor version 0
JDK 1.8 -> major version 52 and minor version 0

You can use javap command to see which version your class is compiled. Then compare with the Java JVM version.

From Open Shift site:

OpenShift uses JBoss EWS 1.0 and 2.0 for Tomcat 6 and 7 respectively. EWS is a hardened and Red Hat supported version of Apache Tomcat. Both versions use Java OpenJDK 1.7.

So, compiling your project with Java 6 or 7 should resolve your problem