It appears that EJB didn't get injected in the AppClient. You need to
take a look at the EJB FAQ [1] which will help you understand how the
injected instance is looked up. To be precise, you will find your answer
at [2].
[1]
https://glassfish.dev.java.net/javaee5/ejb/EJB_FAQ.html
[2]
https://glassfish.dev.java.net/javaee5/ejb/EJB_FAQ.html#EJB_ejb-ref_ejb_local_ref
glassfish_at_javadesktop.org wrote:
> Hi,
>
> A fellow explained me the questions, so it let me develop a simple example.
> It has two entities, a stateless session as facade and the app client.
>
> Every entity map a table.
>
> Here is the code,
>
> 1. package entity;
> 2.
> 3. import java.io.Serializable;
> 4. import javax.persistence.*;
> 5. import static javax.persistence.CascadeType.*;
> 6. import java.util.Collection;
> 7. import java.util.ArrayList;
> 8.
> 9. /**
> 10. *
> 11. * @author NetbeansUser
> 12. */
> 13. @Entity
> 14. public class Customer implements Serializable {
> 15. private int id;
> 16. private String name;
> 17. private Collection<Order> orders = new ArrayList<Order>();
> 18.
> 19. @Id
> 20. public int getId() {
> 21. return id;
> 22. }
> 23.
> 24. public void setId(int id) {
> 25. this.id = id;
> 26. }
> 27.
> 28. public String getName() {
> 29. return name;
> 30. }
> 31.
> 32. public void setName(String name) {
> 33. this.name = name;
> 34. }
> 35.
> 36. @OneToMany(cascade=ALL, mappedBy="customer")
> 37. public Collection<Order> getOrders() {
> 38. return orders;
> 39. }
> 40.
> 41. public void setOrders(Collection<Order> newValue) {
> 42. this.orders = newValue;
> 43. }
> 44.
> 45. @Override
> 46. public int hashCode() {
> 47. int hash = 0;
> 48. hash += (int) id;
> 49. return hash;
> 50. }
> 51.
> 52. @Override
> 53. public boolean equals(Object object) {
> 54. // TODO: Warning - this method won't work in the case the id fields are not set
> 55. if (!(object instanceof Customer)) {
> 56. return false;
> 57. }
> 58. Customer other = (Customer) object;
> 59. if (this.id != other.id) {
> 60. return false;
> 61. }
> 62. return true;
> 63. }
> 64.
> 65. @Override
> 66. public String toString() {
> 67. return "entity.Customer[id=" + id + "]";
> 68. }
> 69.
> 70. }
> --------------------------------------------------------------------------------
> 1. package entity;
> 2.
> 3. import javax.persistence.*;
> 4.
> 5. /**
> 6. *
> 7. * @author NetbeansUser
> 8. */
> 9. @Entity
> 10. @Table(name="ORDER_TABLE")
> 11. public class Order {
> 12.
> 13. private int id;
> 14. private String address;
> 15. private Customer customer;
> 16.
> 17. @Id
> 18. @Column(name="ORDER_ID")
> 19. public int getId() {
> 20. return id;
> 21. }
> 22.
> 23. public void setId(int id) {
> 24. this.id = id;
> 25. }
> 26.
> 27. @Column(name="SHIPPING_ADDRESS")
> 28. public String getAddress() {
> 29. return address;
> 30. }
> 31.
> 32. public void setAddress(String address) {
> 33. this.address = address;
> 34. }
> 35.
> 36. @ManyToOne()
> 37. @JoinColumn(name="CUSTOMER_ID")
> 38. public Customer getCustomer() {
> 39. return customer;
> 40. }
> 41.
> 42. public void setCustomer(Customer customer) {
> 43. this.customer = customer;
> 44. }
> 45. }
>
> -----------------------------------------------------------------------------
> # package ejb;
> #
> # import javax.ejb.Remote;
> # import entity.Customer;
> #
> # /**
> # *
> # * @author NetbeansUser
> # */
> # @Remote
> # public interface Test {
> # // Insert Customer and Orders
> # public String testInsert();
> #
> # // Verify that all are inserted
> # public String verifyInsert();
> #
> # // Remove Customer and Orders
> # public String testDelete(int id);
> #
> # // Verify that all are removed
> # public String verifyDelete();
> #
> # // Get a detached instance of a Customer
> # public int findCustomer(String name);
> #
> # public Customer findCustomer(int id);
> # }
> ----------------------------------------------------------------------------------
> 1. package ejb;
> 2.
> 3. import javax.ejb.Stateless;
> 4. import javax.persistence.EntityManager;
> 5. import javax.persistence.PersistenceContext;
> 6. import javax.persistence.Query;
> 7.
> 8. import java.util.Collection;
> 9. import java.util.List;
> 10.
> 11. import entity.*;
> 12.
> 13. /**
> 14. *
> 15. * @author NetbeansUser
> 16. */
> 17. @Stateless(name="ejb/Test")
> 18. public class TestBean implements Test {
> 19.
> 20. // Add business logic below. (Right-click in editor and choose
> 21. // "Insert Code > Add Business Method" or "Web Service > Add Operation")
> 22. @PersistenceContext(unitName="pu1")
> 23. private EntityManager em;
> 24.
> 25. public String testInsert() {
> 26.
> 27. // Create new customer
> 28. Customer customer0 = new Customer();
> 29. customer0.setId(1);
> 30. customer0.setName("Joe Smith");
> 31.
> 32. // Persist the customer
> 33. em.persist(customer0);
> 34.
> 35. // Create 2 orders
> 36. Order order1 = new Order();
> 37. order1.setId(100);
> 38. order1.setAddress("123 Main St. Anytown, USA");
> 39.
> 40. Order order2 = new Order();
> 41. order2.setId(200);
> 42. order2.setAddress("567 1st St. Random City, USA");
> 43.
> 44. // Associate orders with the customer. The association
> 45. // must be set on both sides of the relationship: on the
> 46. // customer side for the orders to be persisted when
> 47. // transaction commits, and on the order side because it
> 48. // is the owning side.
> 49. customer0.getOrders().add(order1);
> 50. order1.setCustomer(customer0);
> 51.
> 52. customer0.getOrders().add(order2);
> 53. order2.setCustomer(customer0);
> 54.
> 55. return "OK";
> 56. }
> 57.
> 58. public String verifyInsert() {
> 59.
> 60. int id = findCustomer("Joe Smith");
> 61.
> 62. Query q = em.createQuery("select c from Customer c where c.id = :id");
> 63. q.setParameter("name", id);
> 64. Customer c = (Customer)q.getSingleResult();
> 65.
> 66. Collection<Order> orders = c.getOrders();
> 67. if (orders == null || orders.size() != 2) {
> 68. throw new RuntimeException("Unexpected number of orders: "
> 69. + ((orders == null)? "null" : "" + orders.size()));
> 70. }
> 71.
> 72. return "OK";
> 73. }
> 74.
> 75. public String testDelete(int id) {
> 76.
> 77. Customer c = findCustomer(id);
> 78.
> 79. // Merge the customer to the new persistence context
> 80. Customer c0 = em.merge(c);
> 81.
> 82. // Delete all records.
> 83. em.remove(c0);
> 84.
> 85. return "OK";
> 86. }
> 87.
> 88. public String verifyDelete() {
> 89.
> 90. Query q = em.createQuery("select c from Customer c");
> 91. List results = q.getResultList();
> 92.
> 93. if (results == null || results.size() != 0) {
> 94. throw new RuntimeException("Unexpected number of customers after delete");
> 95. }
> 96.
> 97. q = em.createQuery("select o from Order o");
> 98. results = q.getResultList();
> 99.
> 100. if (results == null || results.size() != 0) {
> 101. throw new RuntimeException("Unexpected number of orders after delete");
> 102. }
> 103.
> 104. return "OK";
> 105. }
> 106.
> 107. public int findCustomer(String name) {
> 108.
> 109. Query q = em.createQuery("select c from Customer c where c.name = :name");
> 110. q.setParameter("name", name);
> 111. Customer c = (Customer)q.getSingleResult();
> 112. return c.getId();
> 113. }
> 114.
> 115. public Customer findCustomer(int id){
> 116.
> 117. Query q = em.createQuery("select c from Customer c where c.id = :id");
> 118. q.setParameter("id", id);
> 119. return (Customer)q.getSingleResult();
> 120. }
> 121. }
> ----------------------------------------------------------------------------
> and the client
>
> 1. package client;
> 2.
> 3. import javax.ejb.*;
> 4. import ejb.Test;
> 5.
> 6. /**
> 7. * @author NetbeansUser
> 8. */
> 9. public class AppClient {
> 10.
> 11. @EJB(name="ejb/Test")
> 12. private static Test sb;
> 13.
> 14. public static void main(String[] args) {
> 15. AppClient test = new AppClient();
> 16. test.runTest();
> 17. }
> 18.
> 19.
> 20. public void runTest() {
> 21.
> 22. // Persist all entities
> 23. System.out.println("Inserting Customer and Orders... " + sb.testInsert());
> 24.
> 25. // Test query and navigation
> 26. System.out.println("Verifying that all are inserted... " + sb.verifyInsert());
> 27.
> 28. // Get a detached instance
> 29. int id = sb.findCustomer("Joe Smith");
> 30.
> 31. // Remove all entities
> 32. System.out.println("Removing all... " + sb.testDelete(id));
> 33.
> 34. // Query the results
> 35. System.out.println("Verifying that all are removed... " + sb.verifyDelete());
> 36. }
> 37. }
>
> As you can see it is based on an example form java.net but i tried to separate the entities of the client leaving all the busines logic to the facade.
>
> But it does not work. I get a NullPointerException
> in the call to the facade in the client.
>
> Here is the stacktrace,
>
> 1. 19-feb-2009 11:46:36 com.sun.enterprise.appclient.MainWithModuleSupport <init>
> 2. ADVERTENCIA: ACC003: La aplicación desencadenó una excepción.
> 3. java.lang.NullPointerException
> 4. at client.AppClient.runTest(AppClient.java:28)
> 5. at client.AppClient.main(AppClient.java:21)
> 6. at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> 7. at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
> 8. at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> 9. at java.lang.reflect.Method.invoke(Method.java:597)
> 10. at com.sun.enterprise.util.Utility.invokeApplicationMain(Utility.java:266)
> 11. at com.sun.enterprise.appclient.MainWithModuleSupport.<init>(MainWithModuleSupport.java:449)
> 12. at com.sun.enterprise.appclient.MainWithModuleSupport.<init>(MainWithModuleSupport.java:259)
> 13. at com.sun.enterprise.appclient.Main.main(Main.java:200)
> 14. Exception in thread "main" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
> 15. at com.sun.enterprise.appclient.MainWithModuleSupport.<init>(MainWithModuleSupport.java:461)
> 16. at com.sun.enterprise.appclient.MainWithModuleSupport.<init>(MainWithModuleSupport.java:259)
> 17. at com.sun.enterprise.appclient.Main.main(Main.java:200)
> 18. Caused by: java.lang.reflect.InvocationTargetException
> 19. at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> 20. at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
> 21. at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> 22. at java.lang.reflect.Method.invoke(Method.java:597)
> 23. at com.sun.enterprise.util.Utility.invokeApplicationMain(Utility.java:266)
> 24. at com.sun.enterprise.appclient.MainWithModuleSupport.<init>(MainWithModuleSupport.java:449)
> 25. ... 2 more
> 26. Caused by: java.lang.NullPointerException
> 27. at client.AppClient.runTest(AppClient.java:28)
> 28. at client.AppClient.main(AppClient.java:21)
> 29. ... 8 more
>
> Any idea?
>
> Best regards,
> Jose Alvarez de Lara
> [Message sent by forum member 'josealvarezdelara' (josealvarezdelara)]
>
> http://forums.java.net/jive/thread.jspa?messageID=332875
>
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>