Hot questions for Spring Data

Question:

I am trying to work with Spring Data and Neo4j. I started by trying to follow this guide linked to by the main site. In particular I based my pom.xml off of the "Hello, World!" example file. Here is a snip from my pom.xml for the plugin that is causing the issues...

<plugin>
<!-- Required to resolve aspectj-enhanced class features -->
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>aspectj-maven-plugin</artifactId>
    <version>1.0</version>
    <configuration>
        <outxml>true</outxml>
        <aspectLibraries>
            <aspectLibrary>
                <groupId>org.springframework</groupId>
                <artifactId>spring-aspects</artifactId>
            </aspectLibrary>
            <aspectLibrary>
                <groupId>org.springframework.data</groupId>
                <artifactId>spring-data-neo4j</artifactId>
            </aspectLibrary>
        </aspectLibraries>
        <source>1.6</source>
        <target>1.6</target>
    </configuration>
    <executions>
        <!-- ERROR HERE IN ECLIPSE SEE BELOW FOR FULL MESSAGE -->
        <execution>
            <goals>
                <goal>compile</goal>
                <goal>test-compile</goal>
            </goals>
        </execution>
    </executions>
    <dependencies>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
            <version>${aspectj.version}</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjtools</artifactId>
            <version>${aspectj.version}</version>
        </dependency>
    </dependencies>
</plugin>

The error I am seeing is:

 Multiple annotations found at this line:
    - Plugin execution not covered by lifecycle configuration: org.codehaus.mojo:aspectj-maven-plugin:1.0:compile (execution: default, phase: process-classes)
    - Plugin execution not covered by lifecycle configuration: org.codehaus.mojo:aspectj-maven-plugin:1.0:test-compile (execution: default, phase: process-classes)

I am running Eclipse 3.6.2 and m2e 0.13. I'm not a Maven expert, so please be very explanatory in your answers if possible.

I've also tried m2e 1.0.0 via this update site and still get the same error.


Answer:

In my case of a similar problem, instead of using Andrew's suggestion for the fix, it worked simply after I introduced <pluginManagement> tag to the pom.xml in question. Looks like that error is due to a missing <pluginManagement> tag. So, in order to avoid the exceptions in Eclipse, one needs to simply enclose all the plugin tags inside a <pluginManagement> tag, like so:

<build>
    <pluginManagement>
        <plugins>
            <plugin> ... </plugin>
            <plugin> ... </plugin>
                  ....
        </plugins>
    </pluginManagement>
</build>

Once this structure is in place, the error goes away.

Question:

This is the error that is thrown when trying to run my web app:

[INFO] WARNING: Nested in org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private javax.sql.DataSource org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration.dataSource; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceAutoConfiguration$NonEmbeddedConfiguration.class]: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public javax.sql.DataSource org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration$NonEmbeddedConfiguration.dataSource()] threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Cannot determine embedded database driver class for database type NONE. If you want an embedded database please put a supported one on the classpath.:
    [INFO] org.springframework.beans.factory.BeanCreationException: Cannot determine embedded database driver class for database type NONE. If you want an embedded database please put a supported one on the classpath.
    [INFO]  at org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.getDriverClassName(DataSourceProperties.java:91)
    [INFO]  at org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration$NonEmbeddedConfiguration.dataSource(DataSourceAutoConfiguration.java:100)
    [INFO]  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    [INFO]  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    [INFO]  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    [INFO]  at java.lang.reflect.Method.invoke(Method.java:606)
    [INFO]  at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:115)
    [INFO]  at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:166)
    [INFO]  at org.springframework.beans.factory.support.ConstructorResolver$3.run(ConstructorResolver.java:580)
    [INFO]  at java.security.AccessController.doPrivileged(Native Method)
    [INFO]  at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:577)
    [INFO]  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1094)
    [INFO]  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:989)
    [INFO]  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:504)
    [INFO]  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    [INFO]  at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
    [INFO]  at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    [INFO]  at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
    [INFO]  at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
    [INFO]  at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1017)
    [INFO]  at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:960)
    [INFO]  at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:858)
    [INFO]  at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:480)
    [INFO]  at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
    [INFO]  at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
    [INFO]  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185)
    [INFO]  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
    [INFO]  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    [INFO]  at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
    [INFO]  at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    [INFO]  at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
    [INFO]  at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
    [INFO]  at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:370)
    [INFO]  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1094)
    [INFO]  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:989)
    [INFO]  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:504)
    [INFO]  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    [INFO]  at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
    [INFO]  at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    [INFO]  at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
    [INFO]  at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
    [INFO]  at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:973)
    [INFO]  at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:750)
    [INFO]  at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
    [INFO]  at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:683)
    [INFO]  at org.springframework.boot.SpringApplication.run(SpringApplication.java:313)
    [INFO]  at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:142)
    [INFO]  at org.springframework.boot.legacy.context.web.SpringBootContextLoaderListener.initWebApplicationContext(SpringBootContextLoaderListener.java:60)
    [INFO]  at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
    [INFO]  at org.mortbay.jetty.handler.ContextHandler.startContext(ContextHandler.java:548)
    [INFO]  at org.mortbay.jetty.servlet.Context.startContext(Context.java:136)
    [INFO]  at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1250)
    [INFO]  at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:517)
    [INFO]  at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:467)
    [INFO]  at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    [INFO]  at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
    [INFO]  at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    [INFO]  at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
    [INFO]  at org.mortbay.jetty.Server.doStart(Server.java:224)
    [INFO]  at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    [INFO]  at com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:249)
    [INFO]  at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:306)
    [INFO]  at com.google.appengine.tools.development.AutomaticInstanceHolder.startUp(AutomaticInstanceHolder.java:26)
    [INFO]  at com.google.appengine.tools.development.AbstractModule.startup(AbstractModule.java:79)
    [INFO]  at com.google.appengine.tools.development.Modules.startup(Modules.java:88)
    [INFO]  at com.google.appengine.tools.development.DevAppServerImpl.doStart(DevAppServerImpl.java:254)
    [INFO]  at com.google.appengine.tools.development.DevAppServerImpl.access$000(DevAppServerImpl.java:47)
    [INFO]  at com.google.appengine.tools.development.DevAppServerImpl$1.run(DevAppServerImpl.java:212)
    [INFO]  at com.google.appengine.tools.development.DevAppServerImpl$1.run(DevAppServerImpl.java:210)
    [INFO]  at java.security.AccessController.doPrivileged(Native Method)
    [INFO]  at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:210)
    [INFO]  at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:277)
    [INFO]  at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48)
    [INFO]  at com.google.appengine.tools.development.DevAppServerMain.run(DevAppServerMain.java:219)
    [INFO]  at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:210)

I believe I have the right combination of datanucleus-appengine and datanucleus jars:

2.1: Requires DataNucleus 3.1.x (core, api-jdo, api-jpa, enhancer). Requires SDK 1.6.4+ Note that this release of Datanucleus is no longer supported by the DataNucleus project

JPA App Config:

@Configuration
@EnableJpaRepositories("demo.core.entity")
@EnableTransactionManagement
class JpaApplicationConfig {
    private static final Logger logger = Logger
            .getLogger(JpaApplicationConfig.class.getName());
    @Bean
    public AbstractEntityManagerFactoryBean entityManagerFactory() {
        logger.info("Loading Entity Manager...");
        LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
        factory.setPersistenceUnitName("transactions-optional");
        return factory;
    }
    @Bean
    public PlatformTransactionManager transactionManager() {
        logger.info("Loading Transaction Manager...");
        JpaTransactionManager txManager = new JpaTransactionManager();
        txManager.setEntityManagerFactory(entityManagerFactory().getObject());
        return txManager;
    }
    @Bean
    public PersistenceExceptionTranslator persistenceExceptionTranslator() {
        return new OpenJpaDialect();
    }
}

Application.java

@Configuration
@ComponentScan
@EnableAutoConfiguration
@RestController
public class Application {

    private static final EntityManagerFactory INSTANCE =
            Persistence.createEntityManagerFactory("transactions-optional");

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @RequestMapping("/")
    public String home() {
        return "Hello World";
    }

}

POM:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="...">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.demohq</groupId>
    <artifactId>demo-boot</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>demo-boot</name>
    <description>Demo project</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.1.0.BUILD-SNAPSHOT</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-legacy</artifactId>
            <version>1.1.0.BUILD-SNAPSHOT</version>
        </dependency>
        <!--<dependency>-->
            <!--<groupId>net.kindleit</groupId>-->
            <!--<artifactId>gae-runtime</artifactId>-->
            <!--<version>${gae.version}</version>-->
            <!--<type>pom</type>-->
            <!--<scope>provided</scope>-->
        <!--</dependency>-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
        </dependency>
        <!--<dependency>-->
            <!--<groupId>org.hsqldb</groupId>-->
            <!--<artifactId>hsqldb</artifactId>-->
            <!--<scope>runtime</scope>-->
        <!--</dependency>-->
        <dependency>
            <groupId>com.google.appengine</groupId>
            <artifactId>appengine-api-labs</artifactId>
            <version>${gae.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.google.appengine</groupId>
            <artifactId>appengine-api-stubs</artifactId>
            <version>${gae.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.google.appengine</groupId>
            <artifactId>appengine-testing</artifactId>
            <version>${gae.version}</version>
            <scope>test</scope>
        </dependency>
        <!-- DataNucleus -->
        <dependency>
            <groupId>org.datanucleus</groupId>
            <artifactId>datanucleus-api-jpa</artifactId>
            <version>${datanucleus.jpa.version}</version>
        </dependency>
        <dependency>
            <groupId>org.datanucleus</groupId>
            <artifactId>datanucleus-core</artifactId>
            <version>${datanucleus.jpa.version}</version>
        </dependency>
        <dependency>
            <groupId>org.datanucleus</groupId>
            <artifactId>datanucleus-enhancer</artifactId>
            <version>${datanucleus.jpa.version}</version>
        </dependency>
        <dependency>
            <groupId>com.google.appengine.orm</groupId>
            <artifactId>datanucleus-appengine</artifactId>
            <version>${datanucleus.version}</version>
            <!-- Need to exclude the enhancer since it interfere with the enhancer plugin. -->
            <exclusions>
                <exclusion>
                    <groupId>org.datanucleus</groupId>
                    <artifactId>datanucleus-enhancer</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>javax.jdo</groupId>
            <artifactId>jdo-api</artifactId>
            <version>3.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.geronimo.specs</groupId>
            <artifactId>geronimo-jpa_2.0_spec</artifactId>
            <version>1.1</version>
        </dependency>

        <!-- OpenJPA -->
        <dependency>
            <groupId>org.apache.openjpa</groupId>
            <artifactId>openjpa-persistence</artifactId>
            <version>2.3.0</version>
        </dependency>


    </dependencies>

    <properties>
        <start-class>demo.Application</start-class>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.7</java.version>
        <m2eclipse.wtp.contextRoot>/</m2eclipse.wtp.contextRoot>
        <datanucleus.jpa.version>3.1.1</datanucleus.jpa.version>
        <datanucleus.version>2.1.2</datanucleus.version>
        <gae.version>1.8.8</gae.version>
        <gae.home>${settings.localRepository}/com/google/appengine/appengine-java-sdk/${gae.version}/appengine-java-sdk/appengine-java-sdk-${gae.version}</gae.home>
        <gae.application.version>test</gae.application.version>
        <!--<org.springframework-version>4.0.5.RELEASE</org.springframework-version>-->
    </properties>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <!--
            <plugin>
                <groupId>net.kindleit</groupId>
                <artifactId>maven-gae-plugin</artifactId>
                <version>0.9.6</version>
                <dependencies>
                    <dependency>
                        <groupId>net.kindleit</groupId>
                        <artifactId>gae-runtime</artifactId>
                        <version>${gae.version}</version>
                        <type>pom</type>
                    </dependency>
                </dependencies>
            </plugin>
            -->
            <plugin>
                <groupId>com.google.appengine</groupId>
                <artifactId>appengine-maven-plugin</artifactId>
                <version>${gae.version}</version>
                <configuration>
                    <enableJarClasses>false</enableJarClasses>
                </configuration>
            </plugin>
            <plugin>
                <artifactId>maven-release-plugin</artifactId>
                <configuration>
                    <goals>gae:deploy</goals>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat6-maven-plugin</artifactId>
                <version>2.0</version>
                <configuration>
                    <path>/</path>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.datanucleus</groupId>
                <artifactId>maven-datanucleus-plugin</artifactId>
                <version>${datanucleus.jpa.version}</version>
                <configuration>
                    <api>JPA</api>
                    <!--<mappingIncludes>**/entity/*.class</mappingIncludes>-->
                    <verbose>true</verbose>
                </configuration>
                <dependencies>
                    <dependency>
                        <groupId>org.datanucleus</groupId>
                        <artifactId>datanucleus-core</artifactId>
                        <version>${datanucleus.jpa.version}</version>
                    </dependency>
                </dependencies>
                <executions>
                    <execution>
                        <phase>compile</phase>
                        <goals>
                            <goal>enhance</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

    <profiles>
        <!-- We can configure our integration server to activate this profile and 
            perform gae:deploy, thus uploading latest snapshot to the http://1.latest.<applicationName>.appspot.com 
            automatically -->
        <profile>
            <id>integration-build</id>
            <properties>
                <gae.application.version>stage</gae.application.version>
            </properties>
        </profile>

        <!-- This profile will activate automatically during release and upload 
            application to the http://2.latest.<applicationName>.appspot.com (We might 
            want to set the 2nd version as our applications Default version to be accessible 
            at http://<applicationName>.appspot.com) -->
        <profile>
            <id>release-build</id>
            <activation>
                <property>
                    <name>performRelease</name>
                    <value>true</value>
                </property>
            </activation>

            <properties>
                <!-- During release, set application version in appengine-web.xml to 
                    2 -->
                <gae.application.version>release</gae.application.version>
            </properties>
        </profile>
    </profiles>

    <repositories>
        <repository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>http://repo.spring.io/snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>http://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>http://repo.spring.io/snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </pluginRepository>
        <pluginRepository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>http://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>

</project>

I wonder what could be missing in my app? I followed the instruction from here Using Spring Data JPA on Google Appengine


Answer:

You haven't provided Spring Boot with enough information to auto-configure a DataSource. To do so, you'll need to add some properties to application.properties with the spring.datasource prefix. Take a look at DataSourceProperties to see all of the properties that you can set.

You'll need to provide the appropriate url and driver class name:

spring.datasource.url = …
spring.datasource.driver-class-name = …

Question:

I have a Person class:

@Entity
public class Person {

    @Id
    @GeneratedValue
    private Long id;

    @ManyToMany(fetch = FetchType.LAZY)
    private List<Role> roles;
    // etc
}

With a many-to-many relation that is lazy.

In my controller I have

@Controller
@RequestMapping("/person")
public class PersonController {
    @Autowired
    PersonRepository personRepository;

    @RequestMapping("/get")
    public @ResponseBody Person getPerson() {
        Person person = personRepository.findOne(1L);
        return person;
    }
}

And the PersonRepository is just this code, written according to this guide

public interface PersonRepository extends JpaRepository<Person, Long> {
}

However, in this controller I actually need the lazy-data. How can I trigger its loading?

Trying to access it will fail with

failed to lazily initialize a collection of role: no.dusken.momus.model.Person.roles, could not initialize proxy - no Session

or other exceptions depending on what I try.

My xml-description, in case needed.

Thanks.


Answer:

You will have to make an explicit call on the lazy collection in order to initialize it (common practice is to call .size() for this purpose). In Hibernate there is a dedicated method for this (Hibernate.initialize()), but JPA has no equivalent of that. Of course you will have to make sure that the invocation is done, when the session is still available, so annotate your controller method with @Transactional. An alternative is to create an intermediate Service layer between the Controller and the Repository that could expose methods which initialize lazy collections.

Update:

Please note that the above solution is easy, but results in two distinct queries to the database (one for the user, another one for its roles). If you want to achieve better performace add the following method to your Spring Data JPA repository interface:

public interface PersonRepository extends JpaRepository<Person, Long> {

    @Query("SELECT p FROM Person p JOIN FETCH p.roles WHERE p.id = (:id)")
    public Person findByIdAndFetchRolesEagerly(@Param("id") Long id);

}

This method will use JPQL's fetch join clause to eagerly load the roles association in a single round-trip to the database, and will therefore mitigate the performance penalty incurred by the two distinct queries in the above solution.

Question:

I am using Spring Boot to develop two applications, one serves as the server and other one is a client app. However, both of them are the same app that function differently based on the active profile. I am using auto configuration feature of Spring Boot to configure my applications.

I want to disable all the database related auto configuration on client app, since it won't be requiring database connection. Application should not try to establish connection with the database, nor try to use any of the Spring Data or Hibernate features. The enabling or disabling of the database auto configuration should be conditional and based on the active profile of the app.

Can I achieve this by creating two different application.properties files for respective profiles?

I tried adding this to my properties file,

spring.autoconfigure.exclude=org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration\
  org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration\
org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration\
  org.springframework.boot.autoconfigure.data.web.SpringDataWebAutoConfiguration

But, the application still tries to connect to the database on start. Are those exclusions sufficient for achieving my requirement?


Answer:

The way I would do similar thing is:

@Configuration
@EnableAutoConfiguration(exclude = {DataSourceAutoConfiguration.class, DataSourceTransactionManagerAutoConfiguration.class, HibernateJpaAutoConfiguration.class})
@Profile ("client_app_profile_name")
public class ClientAppConfiguration {
    //it can be left blank
}

Write similar one for the server app (without excludes).

Last step is to disable Auto Configuration from main spring boot class:

@SpringBootApplication
public class SomeApplication extends SpringBootServletInitializer {

    public static void main(String[] args) {
        SpringApplication.run(SomeApplication.class);
    }

    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(SomeApplication.class);
    }
}

Change: @SpringBootApplication into:

@Configuration 
@ComponentScan

This should do the job. Now, the dependencies that I excluded in the example might be incomplete. They were enough for me, but im not sure if its all to completely disable database related libraries. Check the list below to be sure:

http://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/htmlsingle/#auto-configuration-classes

Hope that helps

Question:

I am using Spring JPA for database access. I am able to find examples such as findByName and countByName, for which I dont have to write any method implementation. I am hoping to find examples for delete a group of records based on some condition.

Does Spring JPA support deleteByName-like delete? Any pointer is appreciated.

Regards and thanks.


Answer:

Deprecated answer (Spring Data JPA <=1.6.x):

@Modifying annotation to the rescue. You will need to provide your custom SQL behaviour though.

public interface UserRepository extends JpaRepository<User, Long> {
    @Modifying
    @Query("delete from User u where u.firstName = ?1")
    void deleteUsersByFirstName(String firstName);
}

Update:

In modern versions of Spring Data JPA (>=1.7.x) query derivation for delete, remove and count operations is accessible.

public interface UserRepository extends CrudRepository<User, Long> {

    Long countByFirstName(String firstName);

    Long deleteByFirstName(String firstName);

    List<User> removeByFirstName(String firstName);

}

Question:

I want to write a Spring Data JPA repository interface method signature that will let me find entities with a property of an embedded object in that entity. Does anyone know if this is possible, and if so how?

Here's my code:

@Entity
@Table(name = "BOOK_UPDATE_QUEUE", indexes = { uniqueConstraints = @UniqueConstraint(columnNames = {
        "bookId", "region" }, name = "UK01_BOOK_UPDATE_QUEUE"))
public class QueuedBook implements Serializable {

    @Embedded
    @NotNull
    private BookId bookId;

    ...

}

@Embeddable
public class BookId implements Serializable {

    @NotNull
    @Size(min=1, max=40)
    private String bookId;

    @NotNull
    @Enumerated(EnumType.STRING)
    private Region region;

    ...

}

public interface QueuedBookRepo extends JpaRepository<QueuedBook, Long> {

    //I'd like to write a method like this, but can't figure out how to search by region,
    //when region is actually a part of the embedded BookId
    Page<QueuedBook> findByRegion(Region region, Pageable pageable);

}

Can I write a query for this using Spring Data?


Answer:

This method name should do the trick:

Page<QueuedBook> findByBookIdRegion(Region region, Pageable pageable);

More info on that in the section about query derivation of the reference docs.

Question:

I need to write an application with which I can do complex queries using spring-data and mongodb. I have been starting by using the MongoRepository but struggled with complex queries to find examples or to actually understand the Syntax.

I'm talking about queries like this:

@Repository
public interface UserRepositoryInterface extends MongoRepository<User, String> {
    List<User> findByEmailOrLastName(String email, String lastName);
}

or the use of JSON based queries which I tried by trial and error because I don't get the syntax right. Even after reading the mongodb documentation (non-working example due to wrong syntax).

@Repository
public interface UserRepositoryInterface extends MongoRepository<User, String> {
    @Query("'$or':[{'firstName':{'$regex':?0,'$options':'i'}},{'lastName':{'$regex':?0,'$options':'i'}}]")
    List<User> findByEmailOrFirstnameOrLastnameLike(String searchText);
} 

After reading through all the documentation it seems that mongoTemplate is far better documented then MongoRepository. I'm referring to following documentation:

http://static.springsource.org/spring-data/data-mongodb/docs/current/reference/html/

Can you tell me what is more convenient and powerful to use? mongoTemplate or MongoRepository? Are both same mature or does one of them lack more features then the other?


Answer:

"Convenient" and "powerful to use" are contradicting goals to some degree. Repositories are by far more convenient than templates but the latter of course give you more fine-grained control over what to execute.

As the repository programming model is available for multiple Spring Data modules, you'll find more in-depth documentation for it in the general section of the Spring Data MongoDB reference docs.

TL;DR

We generally recommend the following approach:

  1. Start with the repository abstract and just declare simple queries using the query derivation mechanism or manually defined queries.
  2. For more complex queries, add manually implemented methods to the repository (as documented here). For the implementation use MongoTemplate.

Details

For your example this would look something like this:

  1. Define an interface for your custom code:

    interface CustomUserRepository {
    
      List<User> yourCustomMethod();
    }
    
  2. Add an implementation for this class and follow the naming convention to make sure we can find the class.

    class UserRepositoryImpl implements CustomUserRepository {
    
      private final MongoOperations operations;
    
      @Autowired
      public UserRepositoryImpl(MongoOperations operations) {
    
        Assert.notNull(operations, "MongoOperations must not be null!");
        this.operations = operations;
      }
    
      public List<User> yourCustomMethod() {
        // custom implementation here
      }
    }
    
  3. Now let your base repository interface extend the custom one and the infrastructure will automatically use your custom implementation:

    interface UserRepository extends CrudRepository<User, Long>, CustomUserRepository {
    
    }
    

This way you essentially get the choice: everything that just easy to declare goes into UserRepository, everything that's better implemented manually goes into CustomUserRepository. The customization options are documented here.

Question:

Being new to Spring Boot I am wondering on how I can configure connection details for MongoDB. I have tried the normal examples but none covers the connection details.

I want to specify the database that is going to be used and the url/port of the host that runs MongoDB.

Any hints or tips?


Answer:

Just to quote Boot Docs:

You can set spring.data.mongodb.uri property to change the url, or alternatively specify a host/port. For example, you might declare the following in your application.properties:

spring.data.mongodb.host=mongoserver
spring.data.mongodb.port=27017

All available options for spring.data.mongodb prefix are fields of MongoProperties:

private String host;

private int port = DBPort.PORT;

private String uri = "mongodb://localhost/test";

private String database;

private String gridFsDatabase;

private String username;

private char[] password;

Question:

I have a Spring Data repository method with a native query

@Query(value = "SELECT g.*, gm.* FROM group g LEFT JOIN group_members gm ON g.group_id = gm.group_id and gm.user_id = :userId WHERE g.group_id = :groupId", nativeQuery = true)
    GroupDetails getGroupDetails(@Param("userId") Integer userId, @Param("groupId") Integer groupId);

and I'd like to map the result to Non-Entity POJO GroupDetails.

Is it possible and if so, could you please provide an example ?


Answer:

I think the easiest way to do that is to use so called projection. It can map query results to interfaces. Using SqlResultSetMapping is inconvienient and makes your code ugly :).

An example right from spring data JPA source code:

public interface UserRepository extends JpaRepository<User, Integer> {

   @Query(value = "SELECT firstname, lastname FROM SD_User WHERE id = ?1", nativeQuery = true)
   NameOnly findByNativeQuery(Integer id);

   public static interface NameOnly {

     String getFirstname();

     String getLastname();

  }
}

You can also use this method to get a list of projections.

Check out this spring data JPA docs entry for more info about projections.

Note 1:

Remember to have your User entity defined as normal - the fields from projected interface must match fields in this entity. Otherwise field mapping might be broken (getFirstname() might return value of last name et cetera).

Note 2:

If you use SELECT table.column ... notation always define aliases matching names from entity. For example this code won't work properly (projection will return nulls for each getter):

@Query(value = "SELECT user.firstname, user.lastname FROM SD_User user WHERE id = ?1", nativeQuery = true)
NameOnly findByNativeQuery(Integer id);

But this works fine:

@Query(value = "SELECT user.firstname AS firstname, user.lastname AS lastname FROM SD_User user WHERE id = ?1", nativeQuery = true)
NameOnly findByNativeQuery(Integer id);

In case of more complex queries I'd rather use JdbcTemplate with custom repository instead.

Question:

I just started working on a Spring-data, Hibernate, MySQL, JPA project. I switched to spring-data so that I wouldn't have to worry about creating queries by hand.

I noticed that the use of @Transactional isn't required when you're using spring-data since I also tried my queries without the annotation.

Is there a specific reason why I should/shouldn't be using the @Transactional annotation?

Works:

@Transactional
public List listStudentsBySchool(long id) {
    return repository.findByClasses_School_Id(id);
}

Also works:

public List listStudentsBySchool(long id) {
    return repository.findByClasses_School_Id(id);
}

Thanks in advance!


Answer:

What is your question actually about? The usage of the @Repository annotation or @Transactional.

@Repository is not needed at all as the interface you declare will be backed by a proxy the Spring Data infrastructure creates and activates exception translation for anyway. So using this annotation on a Spring Data repository interface does not have any effect at all.

@Transactional - for the JPA module we have this annotation on the implementation class backing the proxy (SimpleJpaRepository). This is for two reasons: first, persisting and deleting objects requires a transaction in JPA. Thus we need to make sure a transaction is running, which we do by having the method annotated with @Transactional.

Reading methods like findAll() and findOne(…) are using @Transactional(readOnly = true) which is not strictly necessary but triggers a few optimizations in the transaction infrastructure (setting the FlushMode to MANUAL to let persistence providers potentially skip dirty checks when closing the EntityManager). Beyond that the flag is set on the JDBC Connection as well which causes further optimizations on that level.

Depending on what database you use it can omit table locks or even reject write operations you might trigger accidentally. Thus we recommend using @Transactional(readOnly = true) for query methods as well which you can easily achieve adding that annotation to you repository interface. Make sure you add a plain @Transactional to the manipulating methods you might have declared or re-decorated in that interface.

Question:

I have an Entity Class like this:

@Entity
@Table(name = "EMAIL")
class Email{
    @Id
    @Column(name = "Id")
    Long id;
    @Column(name = "EMAIL_ID")
    String emailId;
    @Column(name = "PIN_CODE")
    String pincode;
}

How to write findBy method for the below query using crudrepository spring data jpa?

select email_id,name from email_details where eamil_id in('mike@gmail.com','ram@gmail.com') and pin_code in('633677','733877')

I am expecting the spring data jpa method like the below but how to construct it?

List<Email> findBy.....(List<String> emails, List<String> pinCodes);

I want to get list of Emails in a single database hit.


Answer:

The following signature will do:

List<Email> findByEmailIdInAndPincodeIn(List<String> emails, List<String> pinCodes);

Spring Data JPA supports a large number of keywords to build a query. IN and AND are among them.

Question:

I'm developing application using spring data jpa,hibernate,mysql,tomcat7,maven and it's create error.I'm trying to figure it out but i failed.

error are Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument; No bean named 'entityManagerFactory' is defined; Injection of autowired dependencies failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'initDbService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private org.wahid.cse.repository.RoleRepository org.wahid.cse.service.InitDbService.roleRepository; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'roleRepository': Cannot create inner bean '(inner bean)#c08f81' of type [org.springframework.orm.jpa.SharedEntityManagerCreator] while setting bean property 'entityManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#c08f81': Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'entityManagerFactory' is defined
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:292)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)


 Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private org.wahid.cse.repository.RoleRepository org.wahid.cse.service.InitDbService.roleRepository; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'roleRepository': Cannot create inner bean '(inner bean)#c08f81' of type [org.springframework.orm.jpa.SharedEntityManagerCreator] while setting bean property 'entityManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#c08f81': Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'entityManagerFactory' is defined
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:508)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
... 22 more

 Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'roleRepository': Cannot create inner bean '(inner bean)#c08f81' of type [org.springframework.orm.jpa.SharedEntityManagerCreator] while setting bean property 'entityManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#c08f81': Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'entityManagerFactory' is defined
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:290)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:129)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1456)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1197)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:480)
... 24 more
here is my ApplicationContext.xml file
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:jdbc="http://www.springframework.org/schema/jdbc"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:jpa="http://www.springframework.org/schema/data/jpa"
xsi:schemaLocation="http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-4.0.xsd
    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">

<context:component-scan base-package="org.wahid.cse">
    <context:exclude-filter type="annotation"
        expression="org.springframework.stereotype.Controller" />
</context:component-scan>

<bean id="dataSource" class="org.apache.commons.dbcp2.BasicDataSource"
    destroy-method="close">
    <property name="driverClassName" value="com.mysql.jdbc.Driver" />
    <property name="url" value="jdbc:mysql://localhost:3306/jba" />
    <property name="username" value="root" />
    <property name="password" value="" />
</bean>
<bean id="emf"
    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="packagesToScan" value="org.wahid.cse.entity" />
    <property name="dataSource" ref="dataSource" />

    <property name="jpaProperties">
        <props>
            <prop key="hibernate.show_sql">true</prop>
            <prop key="hibernate.hbm2ddl.auto">create</prop>
            <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
        </props>
    </property>

    <property name="persistenceProvider">
        <bean class="org.hibernate.jpa.HibernatePersistenceProvider"></bean>
    </property>

</bean>
<tx:annotation-driven transaction-manager="transactionManager" />

<bean class="org.springframework.orm.jpa.JpaTransactionManager"
    id="transactionManager">
    <property name="dataSource" ref="dataSource" />
</bean>

Here is pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.ferdous.wahid</groupId>
<artifactId>java-blog-aggregator</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>


<!-- Shared version number properties -->
<properties>
    <org.springframework.version>4.0.5.RELEASE</org.springframework.version>
    <apache.tiles>3.0.4</apache.tiles>
    <servlet-api-version>3.1.0</servlet-api-version>

</properties>

<dependencies>

    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-dbcp2</artifactId>
        <version>2.0.1</version>
    </dependency>



    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.31</version>
    </dependency>



    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-jpa</artifactId>
        <version>1.6.1.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-entitymanager</artifactId>
        <version>4.3.5.Final</version>
    </dependency>

    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>${servlet-api-version}</version>
        <scope>provided</scope>
    </dependency>


    <!-- <dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>javax.servlet.jsp-api</artifactId> 
        <version>2.2.1</version> </dependency> -->

    <dependency>
        <groupId>jstl</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>


    <dependency>
        <groupId>org.apache.tiles</groupId>
        <artifactId>tiles-core</artifactId>
        <version>${apache.tiles}</version>
    </dependency>

    <dependency>
        <groupId>org.apache.tiles</groupId>
        <artifactId>tiles-jsp</artifactId>
        <version>${apache.tiles}</version>
    </dependency>


    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.7.7</version>
    </dependency>


    <!-- Core utilities used by other modules. Define this if you use Spring 
        Utility APIs (org.springframework.core.*/org.springframework.util.*) -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <!-- Expression Language (depends on spring-core) Define this if you use 
        Spring Expression APIs (org.springframework.expression.*) -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-expression</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <!-- Bean Factory and JavaBeans utilities (depends on spring-core) Define 
        this if you use Spring Bean APIs (org.springframework.beans.*) -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-beans</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <!-- Aspect Oriented Programming (AOP) Framework (depends on spring-core, 
        spring-beans) Define this if you use Spring AOP APIs (org.springframework.aop.*) -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aop</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <!-- Application Context (depends on spring-core, spring-expression, spring-aop, 
        spring-beans) This is the central artifact for Spring's Dependency Injection 
        Container and is generally always defined -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <!-- Various Application Context utilities, including EhCache, JavaMail, 
        Quartz, and Freemarker integration Define this if you need any of these integrations -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context-support</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <!-- Transaction Management Abstraction (depends on spring-core, spring-beans, 
        spring-aop, spring-context) Define this if you use Spring Transactions or 
        DAO Exception Hierarchy (org.springframework.transaction.*/org.springframework.dao.*) -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-tx</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <!-- JDBC Data Access Library (depends on spring-core, spring-beans, spring-context, 
        spring-tx) Define this if you use Spring's JdbcTemplate API (org.springframework.jdbc.*) -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <!-- Object-to-Relation-Mapping (ORM) integration with Hibernate, JPA, 
        and iBatis. (depends on spring-core, spring-beans, spring-context, spring-tx) 
        Define this if you need ORM (org.springframework.orm.*) -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-orm</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <!-- Object-to-XML Mapping (OXM) abstraction and integration with JAXB, 
        JiBX, Castor, XStream, and XML Beans. (depends on spring-core, spring-beans, 
        spring-context) Define this if you need OXM (org.springframework.oxm.*) -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-oxm</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <!-- Web application development utilities applicable to both Servlet and 
        Portlet Environments (depends on spring-core, spring-beans, spring-context) 
        Define this if you use Spring MVC, or wish to use Struts, JSF, or another 
        web framework with Spring (org.springframework.web.*) -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <!-- Spring MVC for Servlet Environments (depends on spring-core, spring-beans, 
        spring-context, spring-web) Define this if you use Spring MVC with a Servlet 
        Container such as Apache Tomcat (org.springframework.web.servlet.*) -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <!-- Spring MVC for Portlet Environments (depends on spring-core, spring-beans, 
        spring-context, spring-web) Define this if you use Spring MVC with a Portlet 
        Container (org.springframework.web.portlet.*) -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc-portlet</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <!-- Support for testing Spring applications with tools such as JUnit and 
        TestNG This artifact is generally always defined with a 'test' scope for 
        the integration testing framework and unit testing stubs -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-test</artifactId>
        <version>${org.springframework.version}</version>
        <scope>test</scope>
    </dependency>
</dependencies>
<build>
    <plugins>

        <plugin>
            <groupId>org.apache.tomcat.maven</groupId>
            <artifactId>tomcat7-maven-plugin</artifactId>
            <version>2.2</version>
        </plugin>

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.1</version>
            <configuration>
                <source>1.7</source>
                <target>1.7</target>
            </configuration>
        </plugin>

    </plugins>
</build>

RoleRepository is

import org.springframework.data.jpa.repository.JpaRepository;
import org.wahid.cse.entity.Role;

 public interface RoleRepository extends JpaRepository<Role, Integer>{

 }

Answer:

Spring Data JPA by default looks for an EntityManagerFactory named entityManagerFactory. Check out this part of the Javadoc of EnableJpaRepositories or Table 2.1 of the Spring Data JPA documentation.

That means that you either have to rename your emf bean to entityManagerFactory or change your Spring configuration to:

<jpa:repositories base-package="your.package" entity-manager-factory-ref="emf" /> 

(if you are using XML)

or

@EnableJpaRepositories(basePackages="your.package", entityManagerFactoryRef="emf")

(if you are using Java Config)