java - Cannot create JDBC driver of class '' for connect URL 'null' Error Code: 0 -

i searched , tried lot nothing helps.

i getting "well known" -error. (error code: 0 - no more information)

my persistence-.xml

<?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="jpa_pu" transaction-type="resource_local">         <non-jta-data-source>java:/comp/env/jdbc/jpaconnector</non-jta-data-source>         <!-- <properties> -->         <!-- <property name="eclipselink.target-database" value="sqlserver" /> -->         <!-- <property name="javax.persistence.jdbc.driver" value="com.microsoft.sqlserver.jdbc.sqlserverdriver" /> -->         <!-- <property name="javax.persistence.jdbc.url" value="jdbc:sqlserver://sqlserver01:1433;databasename=db_name" /> -->         <!-- <property name="javax.persistence.jdbc.user" value="jpausr" /> -->         <!-- <property name="javax.persistence.jdbc.password" value="pwd01" /> -->         <!-- </properties> -->     </persistence-unit> </persistence> 

my web.xml

    ...     </servlet-mapping>     <resource-ref>         <res-ref-name>jdbc/jpaconnector</res-ref-name>         <res-type>javax.sql.datasource</res-type>         <res-auth>container</res-auth>     </resource-ref>     ... </web-app> 

my server.xml (catalina_home\conf\server.xml)

<globalnamingresources> <resource name="userdatabase" auth="container"      type="org.apache.catalina.userdatabase" description="user database can updated , saved"      factory="org.apache.catalina.users.memoryuserdatabasefactory" pathname="conf/tomcat-users.xml" />  <resource name="jdbc/jpaconnector" auth="container"      type="javax.sql.datasource" username="jpausr"      password="pwd01" driverclassname="com.microsoft.sqlserver.jdbc.sqlserverdriver"      url="jdbc:sqlserver://sqlserver01:1433;databasename=db_name"      maxactive="8" maxidle="4"/> </globalnamingresources> 

what i've tried:

-use direct way access database (the comment in persistence.xml) ... yes works! think driver , working.

versions:

tomcat 7.0.47

eclipse-link 2.5.2

sql server 2014 express jdbc-driver: 4.0.2206.100