Not able to generate the process instnace from external java class

Hi Redhat Team,

I am not able to generate the process instance from external java class.I am getting the below exception
Exception in thread "main" org.kie.server.api.exception.KieServicesHttpException: Unexpected HTTP response code when requesting URI 'http://localhost:8080/kie-server/services/rest/server/containers/Store_Transfer_KR_MultiItem_1.0.0/processes/Store_Transfer_KR2.Store_Transfer_KR/instances'! Error code: 500, message: "Unable to create response: null"
at org.kie.server.client.impl.AbstractKieServicesClientImpl.createExceptionForUnexpectedResponseCode(AbstractKieServicesClientImpl.java:617)
at org.kie.server.client.impl.AbstractKieServicesClientImpl.makeHttpPostRequestAndCreateCustomResponse(AbstractKieServicesClientImpl.java:320)
at org.kie.server.client.impl.AbstractKieServicesClientImpl.makeHttpPostRequestAndCreateCustomResponse(AbstractKieServicesClientImpl.java:300)
at org.kie.server.client.impl.ProcessServicesClientImpl.startProcess(ProcessServicesClientImpl.java:262)
at com.poc.esteel.elcMain.main(elcMain.java:108)

I follow the below steps:
1)In my business process ,after user task completion .I wrote script task,where i place the ms sql database update java code.
like:
--------------Sript task
System.out.println("Rejected at first level");
System.out.println("Reject 1st level"+Inventory.getApproverName());
System.out.println("Document id"+Inventory.getDocumentId());

java.lang.String DB_URL = "url";
java.lang.String USER = "abc";
java.lang.String PASS = "abc";
try{
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
System.out.println("Connecting to database");
java.sql.Connection conn = java.sql.DriverManager.getConnection(DB_URL,USER,PASS);

System.out.println("Creating statement");
java.sql.Statement stmt = conn.createStatement();
java.lang.String sql = "UPDATE [RETAIL PORTAL].dbo.INVENTORY_CONTROL " +
"SET OVERALL_APPROVAL_STATUS='REJECTED' WHERE DOCUMENT_ID='"+Inventory.getDocumentId()+"'";
int n=stmt.executeUpdate(sql);
System.out.println("rs is:"+n);
stmt.close();
conn.close();
}catch (Exception e) {
e.printStackTrace();
}

---End task

2)Created java class for get the process instnace for :
Java class-------------
public class elcMain {

public static void main(String[] args) {

    Long processInstanceId = null;
    // TODO Auto-generated method stub


    String SERVER_URL = "http://localhost:8080/kie-server/services/rest/server";

    String USERNAME = "kieserver";

    String PASSWORD = "kieserver1!";



    String PROCESS_ID = "Store_Transfer_KR2.Store_Transfer_KR";*/
    /*String CONTAINER_ID = "Store_Transfer_KR_1.0.0";

    String PROCESS_ID = "Store_Transfer_KR2.Store_Transfer_KR";*/
    String CONTAINER_ID ="Store_Transfer_KR_MultiItem_1.0.0";

    String PROCESS_ID="Store_Transfer_KR2.Store_Transfer_KR";
    System.out.println("Initiating the process : " + PROCESS_ID);

    KieServicesConfiguration config = KieServicesFactory.newRestConfiguration(SERVER_URL, USERNAME, PASSWORD);

    Set> allClasses = new HashSet>();

    allClasses.add(Inventory.class);

    allClasses.add(Item.class);


    config.addJaxbClasses(allClasses);

    KieServicesClient client = KieServicesFactory.newKieServicesClient(config);

    ProcessServicesClient processServices = client.getServicesClient(ProcessServicesClient.class);

    Map params = new HashMap();
    Inventory in = new DBConnectWithMultiItem().getData();

    processInstanceId = processServices.startProcess(CONTAINER_ID, PROCESS_ID, params);

        System.out.println("Started New AFFILIATE_DIVISION process " + processInstanceId);


}

}

3)If i add the maven dependency for ms sql server at RHPAM project setting section and try to generate the process instance from java class,in that case above exception.
4)If i dont add the maven dependecy for ms sql database,process instance is generated successfully but databse is not update,it displays ClassNotFoundException for ms sql server class.

Please team help me out.