@PersistenceContext(unitName = "local_dev")
   protected EntityManager manager;

public abstract class PersistenceRepository<T extends Identifiable> implements Repository<T> {

   private Class<T> type;

   protected EntityManager manager;

   public PersistenceRepository(Class<T> type) {
      initEntityManager();
      this.type = type;
   }

   private void initEntityManager() {
      EntityManagerFactory emf = null;
      switch (EnvironmentHelper.ENV_TYPE) {
      case LOCAL:
         emf = Persistence.createEntityManagerFactory("local_dev");
         break;
      case INTEG:
         emf = Persistence.createEntityManagerFactory("local_dev");
         break;
      case PREPROD:
         emf = Persistence.createEntityManagerFactory("preprod");
         break;
      case PROD:
         emf = Persistence.createEntityManagerFactory("prod");
         break;
      default:
         break;
      }

      manager = emf.createEntityManager();

   }

Caused by: javax.ejb.EJBException: org.jboss.weld.exceptions.CreationException: WELD-000079: Could not find the EJB in JNDI:  class com.visiativ.my3dplayer.repository.AttachmentRepository$Proxy$_$$_Weld$EnterpriseProxy$
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.handleExceptionInOurTx(CMTTxInterceptor.java:190) [wildfly-ejb3-8.2.1.Final.jar:8.2.1.Final]
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:275) [wildfly-ejb3-8.2.1.Final.jar:8.2.1.Final]
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.requiresNew(CMTTxInterceptor.java:369) [wildfly-ejb3-8.2.1.Final.jar:8.2.1.Final]
        at org.jboss.as.ejb3.tx.LifecycleCMTTxInterceptor.processInvocation(LifecycleCMTTxInterceptor.java:66) [wildfly-ejb3-8.2.1.Final.jar:8.2.1.Final]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.as.weld.injection.WeldInjectionContextInterceptor.processInvocation(WeldInjectionContextInterceptor.java:43)
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.as.ejb3.component.interceptors.CurrentInvocationContextInterceptor.processInvocation(CurrentInvocationContextInterceptor.java:41) [wildfly-ejb3-8.2.1.Final.jar:8.2.1.Final]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.as.ee.concurrent.ConcurrentContextInterceptor.processInvocation(ConcurrentContextInterceptor.java:45) [wildfly-ee-8.2.1.Final.jar:8.2.1.Final]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.invocation.ContextClassLoaderInterceptor.processInvocation(ContextClassLoaderInterceptor.java:64) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.invocation.InterceptorContext.run(InterceptorContext.java:326) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.invocation.PrivilegedWithCombinerInterceptor.processInvocation(PrivilegedWithCombinerInterceptor.java:80) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.as.ee.component.BasicComponent.constructComponentInstance(BasicComponent.java:160) [wildfly-ee-8.2.1.Final.jar:8.2.1.Final]
        ... 11 more
Caused by: org.jboss.weld.exceptions.CreationException: WELD-000079: Could not find the EJB in JNDI:  class com.visiativ.my3dplayer.repository.AttachmentRepository$Proxy$_$$_Weld$EnterpriseProxy$
        at org.jboss.weld.injection.producer.ejb.SessionBeanProxyInstantiator.newInstance(SessionBeanProxyInstantiator.java:69) [weld-core-impl-2.2.6.Final.jar:2014-10-03 10:05]
        at org.jboss.weld.bean.SessionBean.create(SessionBean.java:149) [weld-core-impl-2.2.6.Final.jar:2014-10-03 10:05]
        at org.jboss.weld.context.unbound.DependentContextImpl.get(DependentContextImpl.java:69) [weld-core-impl-2.2.6.Final.jar:2014-10-03 10:05]
        at org.jboss.weld.manager.BeanManagerImpl.getReference(BeanManagerImpl.java:742) [weld-core-impl-2.2.6.Final.jar:2014-10-03 10:05]
        at org.jboss.weld.manager.BeanManagerImpl.getInjectableReference(BeanManagerImpl.java:840) [weld-core-impl-2.2.6.Final.jar:2014-10-03 10:05]
        at org.jboss.weld.injection.FieldInjectionPoint.inject(FieldInjectionPoint.java:92) [weld-core-impl-2.2.6.Final.jar:2014-10-03 10:05]
        at org.jboss.weld.util.Beans.injectBoundFields(Beans.java:370) [weld-core-impl-2.2.6.Final.jar:2014-10-03 10:05]
        at org.jboss.weld.util.Beans.injectFieldsAndInitializers(Beans.java:381) [weld-core-impl-2.2.6.Final.jar:2014-10-03 10:05]
        at org.jboss.weld.injection.producer.DefaultInjector$1.proceed(DefaultInjector.java:71) [weld-core-impl-2.2.6.Final.jar:2014-10-03 10:05]
        at org.jboss.weld.injection.InjectionContextImpl.run(InjectionContextImpl.java:48) [weld-core-impl-2.2.6.Final.jar:2014-10-03 10:05]
        at org.jboss.weld.injection.producer.DefaultInjector.inject(DefaultInjector.java:73) [weld-core-impl-2.2.6.Final.jar:2014-10-03 10:05]
        at org.jboss.weld.injection.producer.ejb.SessionBeanInjectionTarget.inject(SessionBeanInjectionTarget.java:140) [weld-core-impl-2.2.6.Final.jar:2014-10-03 10:05]
        at org.jboss.as.weld.injection.WeldInjectionContext.inject(WeldInjectionContext.java:39)
        at org.jboss.as.weld.injection.WeldInjectionInterceptor.processInvocation(WeldInjectionInterceptor.java:51)
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.as.ee.component.AroundConstructInterceptorFactory$1.processInvocation(AroundConstructInterceptorFactory.java:28) [wildfly-ee-8.2.1.Final.jar:8.2.1.Final]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.as.weld.injection.WeldInterceptorInjectionInterceptor.processInvocation(WeldInterceptorInjectionInterceptor.java:56)
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.as.weld.ejb.Jsr299BindingsCreateInterceptor.processInvocation(Jsr299BindingsCreateInterceptor.java:94)
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.as.ee.component.NamespaceContextInterceptor.processInvocation(NamespaceContextInterceptor.java:50) [wildfly-ee-8.2.1.Final.jar:8.2.1.Final]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:309) [jboss-invocation-1.2.1.Final.jar:1.2.1.Final]
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:273) [wildfly-ejb3-8.2.1.Final.jar:8.2.1.Final]
        ... 27 more
Caused by: javax.persistence.PersistenceException: Could not set provided connection [org.jboss.jca.adapters.jdbc.jdk7.WrappedConnectionJDK7@63454e9f] to auto-commit mode (needed for schema generation)
        at org.hibernate.jpa.internal.schemagen.JpaSchemaGenerator$ConnectionProviderJdbcConnectionAccess.<init>(JpaSchemaGenerator.java:709)
        at org.hibernate.jpa.internal.schemagen.JpaSchemaGenerator$ConnectionProviderJdbcConnectionAccess.<init>(JpaSchemaGenerator.java:686)
        at org.hibernate.jpa.internal.schemagen.JpaSchemaGenerator.determineAppropriateJdbcConnectionContext(JpaSchemaGenerator.java:413)
        at org.hibernate.jpa.internal.schemagen.JpaSchemaGenerator.access$100(JpaSchemaGenerator.java:69)
        at org.hibernate.jpa.internal.schemagen.JpaSchemaGenerator$Generation.execute(JpaSchemaGenerator.java:122)
        at org.hibernate.jpa.internal.schemagen.JpaSchemaGenerator.performGeneration(JpaSchemaGenerator.java:76)
        at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:859)
        at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:845)
        at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.withTccl(ClassLoaderServiceImpl.java:398)
        at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:844)
        at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:75)
        at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:55) [hibernate-jpa-2.1-api-1.0.0.Final.jar:1.0.0.Final]
        at com.visiativ.my3dplayer.repository.core.PersistenceRepository.initEntityManager(PersistenceRepository.java:38)
        at com.visiativ.my3dplayer.repository.core.PersistenceRepository.<init>(PersistenceRepository.java:27)
        at com.visiativ.my3dplayer.repository.AttachmentRepository.<init>(AttachmentRepository.java:24)
        at com.visiativ.my3dplayer.repository.AttachmentRepository$Proxy$_$$_Weld$EnterpriseProxy$.<init>(Unknown Source)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) [rt.jar:1.8.0_77]
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) [rt.jar:1.8.0_77]
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) [rt.jar:1.8.0_77]
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423) [rt.jar:1.8.0_77]
        at java.lang.Class.newInstance(Class.java:442) [rt.jar:1.8.0_77]
        at org.jboss.weld.security.NewInstanceAction.run(NewInstanceAction.java:33) [weld-core-impl-2.2.6.Final.jar:2014-10-03 10:05]
        at java.security.AccessController.doPrivileged(Native Method) [rt.jar:1.8.0_77]
        at org.jboss.weld.injection.producer.ejb.SessionBeanProxyInstantiator.newInstance(SessionBeanProxyInstantiator.java:56) [weld-core-impl-2.2.6.Final.jar:2014-10-03 10:05]
        ... 50 more
Caused by: java.sql.SQLException: You cannot set autocommit during a managed transaction!
        at org.jboss.jca.adapters.jdbc.BaseWrapperManagedConnection.setJdbcAutoCommit(BaseWrapperManagedConnection.java:968)
        at org.jboss.jca.adapters.jdbc.WrappedConnection.setAutoCommit(WrappedConnection.java:716)
        at org.hibernate.jpa.internal.schemagen.JpaSchemaGenerator$ConnectionProviderJdbcConnectionAccess.<init>(JpaSchemaGenerator.java:706)
        ... 73 more

07:43:50,067 ERROR [org.jboss.as.controller.management-operation] (management-handler-thread - 1) JBAS014613: Operation ("deploy") failed - address: ([("deployment" => "my3dplayer.war")]) - failure description: {"JBAS014671: Failed services" => {"jboss.deployment.unit.\"my3dplayer.war\".component.InitDefaultSampleThumbs.START" => "org.jboss.msc.service.StartException in service jboss.deployment.unit.\"my3dplayer.war\".component.InitDefaultSampleThumbs.START: java.lang.IllegalStateException: JBAS011048: Failed to construct component instance
    Caused by: java.lang.IllegalStateException: JBAS011048: Failed to construct component instance
    Caused by: javax.ejb.EJBException: org.jboss.weld.exceptions.CreationException: WELD-000079: Could not find the EJB in JNDI:  class com.visiativ.my3dplayer.repository.AttachmentRepository$Proxy$_$$_Weld$EnterpriseProxy$
    Caused by: org.jboss.weld.exceptions.CreationException: WELD-000079: Could not find the EJB in JNDI:  class com.visiativ.my3dplayer.repository.AttachmentRepository$Proxy$_$$_Weld$EnterpriseProxy$
    Caused by: javax.persistence.PersistenceException: Could not set provided connection [org.jboss.jca.adapters.jdbc.jdk7.WrappedConnectionJDK7@63454e9f] to auto-commit mode (needed for schema generation)
    Caused by: java.sql.SQLException: You cannot set autocommit during a managed transaction!"}}
07:43:50,073 ERROR [org.jboss.as.server] (management-handler-thread - 1) JBAS015870: Deploy of deployment "my3dplayer.war" was rolled back with the following failure message:
{"JBAS014671: Failed services" => {"jboss.deployment.unit.\"my3dplayer.war\".component.InitDefaultSampleThumbs.START" => "org.jboss.msc.service.StartException in service jboss.deployment.unit.\"my3dplayer.war\".component.InitDefaultSampleThumbs.START: java.lang.IllegalStateException: JBAS011048: Failed to construct component instance
    Caused by: java.lang.IllegalStateException: JBAS011048: Failed to construct component instance
    Caused by: javax.ejb.EJBException: org.jboss.weld.exceptions.CreationException: WELD-000079: Could not find the EJB in JNDI:  class com.visiativ.my3dplayer.repository.AttachmentRepository$Proxy$_$$_Weld$EnterpriseProxy$
    Caused by: org.jboss.weld.exceptions.CreationException: WELD-000079: Could not find the EJB in JNDI:  class com.visiativ.my3dplayer.repository.AttachmentRepository$Proxy$_$$_Weld$EnterpriseProxy$
    Caused by: javax.persistence.PersistenceException: Could not set provided connection [org.jboss.jca.adapters.jdbc.jdk7.WrappedConnectionJDK7@63454e9f] to auto-commit mode (needed for schema generation)
    Caused by: java.sql.SQLException: You cannot set autocommit during a managed transaction!"}}

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1"
   xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="
        http://xmlns.jcp.org/xml/ns/persistence
        http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">

   <persistence-unit name="local_dev">

      <!-- <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider> -->
      <provider>org.hibernate.ejb.HibernatePersistence</provider>

      <jta-data-source>java:jboss/datasources/MySQLDS</jta-data-source>

      <properties>
         <!-- <property name="hibernate.hbm2ddl.auto" value="update" /> -->
         <!-- <property name="hibernate.connection.autocommit" value="after_transaction"
            /> -->
         <!-- <property name="hibernate.show_sql" value="false" /> -->
         <!-- more info on generation ppts: https://www.google.com/search?q=javax.persistence.schema-generation.drop-source&ie=utf-8&oe=utf-8 -->
         <!-- <property name="javax.persistence.schema-generation.database.action" -->
         <!-- value="drop-and-create" /> -->
         <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect" />
         <property name="javax.persistence.schema-generation.database.action"
            value="drop-and-create" />
         <property name="javax.persistence.schema-generation.scripts.action"
            value="drop-and-create" />
         <property name="javax.persistence.schema-generation.create-source"
            value="metadata" />
         <property name="javax.persistence.schema-generation.drop-source"
            value="metadata" />
         <!-- <property name="javax.persistence.schema-generation-target" value="database"/> -->

         <!-- for script generation -->
         <property name="javax.persistence.schema-generation-target"
            value="database-and-scripts" />
         <property name="javax.persistence.schema-generation.scripts.create-target"
            value="file:/c:/tmp/sql/create.ddl" />
         <property name="javax.persistence.schema-generation.scripts.drop-target"
            value="file:/c:/tmp/sql/drop.ddl" />
         <property
            name="javax.persistence.schema-generation.create-database-schemas"
            value="true" />

         <!-- Populate the database -->
         <property name="javax.persistence.sql-load-script-source"
            value="sql/load.sql" />
      </properties>

   </persistence-unit>

   <persistence-unit name="preprod">
      <!-- <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider> -->
      <provider>org.hibernate.ejb.HibernatePersistence</provider>
      <jta-data-source>java:jboss/datasources/MySQLDS</jta-data-source>

      <properties>
         <property name="hibernate.show_sql" value="false" />
         <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect" />

      </properties>

   </persistence-unit>

   <persistence-unit name="prod">

      <!-- <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider> -->
      <provider>org.hibernate.ejb.HibernatePersistence</provider>
      <jta-data-source>java:jboss/datasources/MySQLDS</jta-data-source>

      <properties>
         <property name="hibernate.show_sql" value="false" />
         <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect" />
      </properties>
   </persistence-unit>

</persistence>

@Produces
public EntityManager create() {
    //read some property from the database and then construct your entity manager based upon the property
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("persistence unit name which you want based upon something");
        EntityManager em = emf.createEntityManager();
       
        return em;
}