No plugin found for prefix org.codehaus.mojo

[José Luis Cetina]

Im trying to create my Entities from my database with Maven but i always
get an error, somebody knows what can be?

when i use:
mvn org.codehaus.mojo:exec-maven-plugin

i get this error:

No plugin found for prefix 'org.codehaus.mojo' in the current project and
in the plugin groups [org.apache.maven.plugins, org.codehaus.mojo]
available from the repositories [local (C:\Users\user\.m2\repository),
central (http://repo.maven.apache.org/maven2)]

here is my pom.xml

<plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>exec-maven-plugin</artifactId>
                <version>1.2</version>
                <configuration>

<mainClass>org.apache.openjpa.jdbc.meta.ReverseMappingTool</mainClass>
                    <commandlineArgs>
                        -directory src/main/java -accessType fields
                        -useGenericCollections true -package
org.yourproject.model
                        -metadata none -annotations true
                        -innerIdentityClasses false
-useBuiltinIdentityClass false
                        -primaryKeyOnJoin false
                    </commandlineArgs>

<includePluginDependencies>true</includePluginDependencies>
                </configuration>
                <dependencies>
                    <dependency>
                        <groupId>javax.validation</groupId>
                        <artifactId>validation-api</artifactId>
                        <version>1.0.CR3</version>
                    </dependency>
                    <dependency>
                        <groupId>org.apache.openjpa</groupId>
                        <artifactId>openjpa-all</artifactId>
                        <version>2.0.1</version>
                    </dependency>
                </dependencies>
            </plugin>

-- 
-------------------------------------------------------------------
*SCJA. José Luis Cetina*
-------------------------------------------------------------------