public List getAllDepartmentsHavingEmployees(){
        JpaEntityManager jpaEntityManager =
            (JpaEntityManager)em.getDelegate();
        Query query =
            jpaEntityManager.createNamedQuery("Departments.allDepartmentsHavingEmployees");
        JavaBeanResult.setQueryResultClass(query, AggregatedDepartment.class);
        return query.getResultList();
    }
  

@Entity
@NamedQueries( { @NamedQuery(name = "Departments.findAll", query = "select o from Departments o")
                 })
@NamedNativeQueries({
                       @NamedNativeQuery(name="Departments.allDepartmentsHavingEmployees", query = "select e.department_id, d.department_name ,  sum(e.salary), avg(e.salary) , max(e.salary), min(e.salary) from departments d , employees e where d.department_id = e.department_id group by e.department_id, d.department_name")})
public class Departments implements Serializable {...}

package oramag.sample.dashboard.model;

import java.io.Serializable;

import java.math.BigDecimal;


public class AggregatedDepartment implements Serializable{

    @SuppressWarnings("compatibility:5167698678781240729")
    private static final long serialVersionUID = 1L;
    
    private BigDecimal departmentId;
    private String departmentName;
    private BigDecimal sum;
    private BigDecimal avg;
    private BigDecimal max;
    private BigDecimal min;
    
    public AggregatedDepartment() {
        super();
    }

    public AggregatedDepartment(BigDecimal departmentId, String departmentName, BigDecimal sum, BigDecimal avg,
                                BigDecimal max, BigDecimal min) {
        super();
        this.departmentId = departmentId;
        this.departmentName = departmentName;
        this.sum = sum;
        this.avg = avg;
        this.max = max;
        this.min = min;
    }

    public void setDepartmentId(BigDecimal departmentId) {
        this.departmentId = departmentId;
    }

    public BigDecimal getDepartmentId() {
        return departmentId;
    }

    public void setDepartmentName(String departmentName) {
        this.departmentName = departmentName;
    }

    public String getDepartmentName() {
        return departmentName;
    }

    public void setSum(BigDecimal sum) {
        this.sum = sum;
    }

    public BigDecimal getSum() {
        return sum;
    }

    public void setAvg(BigDecimal avg) {
        this.avg = avg;
    }

    public BigDecimal getAvg() {
        return avg;
    }

    public void setMax(BigDecimal max) {
        this.max = max;
    }

    public BigDecimal getMax() {
        return max;
    }

    public void setMin(BigDecimal min) {
        this.min = min;
    }

    public BigDecimal getMin() {
        return min;
    }
}

package oramag.sample.dashboard.model.util;

/*******************************************************************************
  * Copyright (c) 2010 Oracle. All rights reserved.
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
  * which accompanies this distribution.
  * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
  * and the Eclipse Distribution License is available at
  * http://www.eclipse.org/org/documents/edl-v10.php.
  *
  * @author shsmith
  ******************************************************************************/

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;

import java.util.ArrayList;
import java.util.List;


import javax.persistence.Query;

import org.eclipse.persistence.exceptions.ConversionException;
import org.eclipse.persistence.internal.helper.ConversionManager;
import org.eclipse.persistence.internal.sessions.AbstractRecord;
import org.eclipse.persistence.internal.sessions.AbstractSession;
import org.eclipse.persistence.jpa.JpaHelper;
import org.eclipse.persistence.queries.DatabaseQuery;
import org.eclipse.persistence.queries.QueryRedirector;
import org.eclipse.persistence.sessions.Record;
import org.eclipse.persistence.sessions.Session;


/***
 * This class is a simple query redirector that intercepts the result of a
 * native query and builds an instance of the specified JavaBean class from each
 * result row. The order of the selected columns musts match the JavaBean class
 * constructor arguments order.
 *
 * To configure a JavaBeanResult on a native SQL query use:
 *    JavaBeanResult.setQueryResultClass(query, SomeBeanClass.class);
 * where query is either a JPA SQL Query or native EclipseLink DatabaseQuery.
 *
 * @author shsmith
 *
 */  
 public final class JavaBeanResult implements QueryRedirector {  
    private static final long serialVersionUID = 3025874987115503731L;  
    protected Class resultClass;  
    public static void setQueryResultClass(Query query, Class resultClass) {  
       JavaBeanResult javaBeanResult = new JavaBeanResult(resultClass);  
       DatabaseQuery databaseQuery = JpaHelper.getDatabaseQuery(query);  
       databaseQuery.setRedirector(javaBeanResult);  
    }  
    public static void setQueryResultClass(DatabaseQuery query,  
          Class resultClass) {  
       JavaBeanResult javaBeanResult = new JavaBeanResult(resultClass);  
       query.setRedirector(javaBeanResult);  
    }  
    protected JavaBeanResult(Class resultClass) {  
       this.resultClass = resultClass;  
    }  
    @SuppressWarnings("unchecked")  
    public Object invokeQuery(DatabaseQuery query, Record arguments,  
          Session session) {  
       List