JPA entity class - org.hibernate.ejb.QueryImpl cannot be cast error

try {
			
		 Users result = (Users) entityManager.createQuery("select users.userName, users.userPassword from Users users");//------------> throws exception
		
		 System.out.println("credentials.getUsername(): " + credentials.getUsername());
		 System.out.println("result.getUserPassword(): " + result.getUserPassword());
		 
		 
		 log.debug("Authentication successful:" + credentials.getUsername());
		 return true;
} catch (Exception e) {
		 log.debug("Failed to authenticate user:" + credentials.getUsername());
		
		 System.out.println("Exception: " + e.getMessage());
				
		
		 return false;
		 }
 
++++++++++++++++++++++++++++
...
...
 
@Entity
@Name("users")
public class Users {
	@Id
	@GeneratedValue	
	
	private Integer id;
	
 
	@NotEmpty	
	private String userName;
	
	@NotEmpty
	private String userPassword;
	
	@NotEmpty
	private String firstName;
	
	@NotEmpty
	private String lastName;
	
	@NotEmpty
	private String agencyName;
	
	@NotEmpty
	private boolean acctEnabledFlag;
	private Date dob;
	
	@NotEmpty
	private String userType;
	private String note;
	
	@NotEmpty
	private Date created;
	
	
	/**
	 * @return the id
	 */
	@Id
	@GeneratedValue	
	//@Column(name="USERS_ID")
	public Integer getId() {
		return id;
	}
	/**
	 * @param id the usersId to set
	 */
	public void setId(Integer id) {
		this.id = id;
	}
	
	/**
	 * @return the created
	 */
	public Date getCreated() {
		return created;
	}
	/**
	 * @param created the created to set
	 */
	public void setCreated(Date created) {
		this.created = created;
	}
	/**
	 * @return the note
	 */
	public String getNote() {
		return note;
	}
	/**
	 * @param note the note to set
	 */
	public void setNote(String note) {
		this.note = note;
	}
	
	/**
	 * @return the userName
	 */	
	public String getUserName() {
		return userName;
	}
	/**
	 * @param userName the userName to set
	 */
	@UserPrincipal
	public void setUserName(String userName) {
		this.userName = userName;
	}
	/**
	 * @return the userPassword
	 */
	 @UserPassword(hash="none")
	public String getUserPassword() {
		return userPassword;
	}
	/**
	 * @param userPassword the userPassword to set
	 */
	public void setUserPassword(String userPassword) {
		this.userPassword = userPassword;
	}
	/**
	 * @return the firstName
	 */
	@UserFirstName
	public String getFirstName() {
		return firstName;
	}
	/**
	 * @param firstName the firstName to set
	 */
	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}
	/**
	 * @return the lastName
	 */
	@UserLastName
	public String getLastName() {
		return lastName;
	}
	/**
	 * @param lastName the lastName to set
	 */
	public void setLastName(String lastName) {
		this.lastName = lastName;
	}
	/**
	 * @return the agencyName
	 */
	public String getAgencyName() {
		return agencyName;
	}
	/**
	 * @param agencyName the agencyName to set
	 */
	public void setAgencyName(String agencyName) {
		this.agencyName = agencyName;
	}
	/**
	 * @return the acctEnabledFlag
	 */
	@UserEnabled
	public boolean isAcctEnabledFlag() {
		return acctEnabledFlag;
	}
	/**
	 * @param acctEnabledFlag the acctEnabledFlag to set
	 */
	public void setAcctEnabledFlag(boolean acctEnabledFlag) {
		this.acctEnabledFlag = acctEnabledFlag;
	}
	/**
	 * @return the dob
	 */
	public Date getDob() {
		return dob;
	}
	/**
	 * @param dob the dob to set
	 */
	public void setDob(Date dob) {
		this.dob = dob;
	}
	/**
	 * @return the userType
	 */
	public String getUserType() {
		return userType;
	}
	/**
	 * @param userType the userType to set
	 */
	public void setUserType(String userType) {
		this.userType = userType;
	}
	
}