title: org.hibernate.MappingException: Unknown entity on User object that contains Entity annotation
body: <p>i am scratching my head wondering why this exception keeps popping up whenever i try to save a new user to my DB using spring and hibernate.</p>
  
  <p>i have double checked and made sure @Entity annotation is present and even added @Table annoation to say which table this object belongs to and i am still recieving this error</p>
  
  <p>below is my user object:</p>
  
  <pre><code>    @Entity
  @Table(name = "USER")
  public class User implements Serializable {
  
      /**
       * Serial version
       */
      private static final long serialVersionUID = 1L;
  
      @JsonElement(type = JsonElementType.JSON_KEY)
      public static final String KEY_BIO = "Bio";
  
      @JsonElement(type = JsonElementType.JSON_KEY)
      public static final String SURNAME = "Surname";
  
      @JsonElement(type = JsonElementType.JSON_KEY)
      public static final String KEY_FIRST_NAME = "FirstName";
  
      @JsonElement(type = JsonElementType.JSON_KEY)
      public static final String KEY_PASSWORD = "Password";
  
      @JsonElement(type = JsonElementType.JSON_KEY)
      public static final String KEY_EMAIL = "EmailAddress";
  
      @JsonElement(type = JsonElementType.JSON_KEY)
      public static final String KEY_USERNAME = "Username";
  
      @JsonElement(type = JsonElementType.JSON_KEY)
      public static final String KEY_USER_ID = "UserId";
  
      @JsonElement(type = JsonElementType.JSON_KEY)
      public static final int USERNAME_LENGTH = 5;
  
      @Id
      @Column(name = "USER_ID")
      @NotNull
      private String id;
  
      @Column(name = "USERNAME", nullable = false, unique = true)
      @NotNull
      private String username;
  
      @Column(name = "EMAIL_ADDRESS", nullable = false, unique = true)
      @NotNull
      private String emailAddress;
  
      @Column(name = "PASSWORD")
      @NotNull
      @Size(min = 5, max = 25)
      private String password;
  
      @Column(name = "FIRST_NAME")
      private String firstName;
  
      @Column(name = "SURNAME")
      private String surname;
  
      @Column(name = "COUNTRY")
      private String country;
  
      @Column(name = "BIO")
      private String bio;
  
  
  
      @Column(name = "SESSION_ID")
      private String sessionId;
  
      @Column(name = "LAST_REST_CALL_MADE")
      private Date lastRestCallMade;
  
      @Column(name = "STATUS")
      @NotNull
      private int status;
  
      @OneToOne
      @JoinColumn(name = "imageId")
      private ProfileImage profileImage;
  
      public User() {
          id = UUID.randomUUID().toString();
      }
  
      @JsonElement(type = JsonElementType.GETTER)
      public ProfileImage getProfileImage() {
          return profileImage;
      }
  
      @JsonElement(type = JsonElementType.SETTER)
      public void setProfileImage(ProfileImage profileImage) {
          this.profileImage = profileImage;
      }
  
      @JsonElement(type = JsonElementType.GETTER)
      public String getId() {
          return id;
      }
  
      @JsonElement(type = JsonElementType.SETTER)
      public void setId(String id) {
          this.id = id;
      }
  
      @JsonElement(type = JsonElementType.GETTER)
      public String getUsername() {
          return username;
      }
  
      @JsonElement(type = JsonElementType.SETTER)
      public void setUsername(String username) {
          this.username = username;
      }
  
      @JsonElement(type = JsonElementType.GETTER)
      public String getEmailAddress() {
          return emailAddress;
      }
  
      @JsonElement(type = JsonElementType.SETTER)
      public void setEmailAddress(String emailAddress) {
          this.emailAddress = emailAddress;
      }
  
      @JsonElement(type = JsonElementType.GETTER)
      public String getPassword() {
          return password;
      }
  
      @JsonElement(type = JsonElementType.SETTER)
      public void setPassword(String password) {
          this.password = password;
      }
  
      @JsonElement(type = JsonElementType.GETTER)
      public String getFirstName() {
          return firstName;
      }
  
      @JsonElement(type = JsonElementType.SETTER)
      public void setFirstName(String firstName) {
          this.firstName = firstName;
      }
  
      @JsonElement(type = JsonElementType.GETTER)
      public String getSurname() {
          return surname;
      }
  
      @JsonElement(type = JsonElementType.SETTER)
      public void setSurname(String surname) {
          this.surname = surname;
      }
  
      @JsonElement(type = JsonElementType.GETTER)
      public String getBio() {
          return bio;
      }
  
      @JsonElement(type = JsonElementType.SETTER)
      public void setBio(String bio) {
          this.bio = bio;
      }
  
      @JsonElement(type = JsonElementType.GETTER)
      public String getCountry() {
          return country;
      }
  
      @JsonElement(type = JsonElementType.SETTER)
      public void setCountry(String country) {
          this.country = country;
      }
  
      /**
       * @return the sessionId
       */
      public String getSessionId() {
          return sessionId;
      }
  
      /**
       * @param sessionId the sessionId to set
       */
      @JsonElement(type = JsonElementType.SETTER)
      public void setSessionId(String sessionId) {
          this.sessionId = sessionId;
      }
  
      /**
       * @return the lastRestCallMade
       */
      public Date getLastRestCallMade() {
          return lastRestCallMade;
      }
  
      /**
       * @param lastRestCallMade the lastRestCallMade to set
       */
      public void setLastRestCallMade(Date lastRestCallMade) {
          this.lastRestCallMade = lastRestCallMade;
      }
  
      /**
       * @return the status
       */
      public int getStatus() {
          return status;
      }
  
      /**
       * @param status the status to set
       */
      public void setStatus(int status) {
          this.status = status;
      }
  
  }
  </code></pre>
  
  <p>here is what my userDao does</p>
  
  <pre><code>@Override
      public void addNewUser(User user) throws InvalidDataException {
          // TODO: Add Transaction manager object here either using annototation
          // or creating it programatically
  
          if (mSessionFactory != null) {
              session = mSessionFactory.getCurrentSession();
              session.beginTransaction();
              if (user.getUsername() == null
                      || user.getUsername().length() &lt; User.USERNAME_LENGTH) {
                  throw new InvalidDataException(
                          InvalidDataException.ERROR_USERNAME_NULL);
              }
  
              session.save(user);
  
          }else{
              throw new RuntimeException("mSession is null");
          }
      }
  </code></pre>
  
  <p>pretty simple suff here.</p>
  
  <p>full stracktrace below:</p>
  
  <pre><code>org.hibernate.MappingException: Unknown entity: com.jr.freedom.user.User
      at org.hibernate.internal.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:1092)
      at org.hibernate.internal.SessionImpl.getEntityPersister(SessionImpl.java:1399)
      at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:117)
      at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:204)
      at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:55)
      at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:189)
      at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:49)
      at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:90)
      at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:753)
      at org.hibernate.internal.SessionImpl.save(SessionImpl.java:745)
      at org.hibernate.internal.SessionImpl.save(SessionImpl.java:741)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
      at java.lang.reflect.Method.invoke(Method.java:597)
      at org.hibernate.context.internal.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:352)
      at $Proxy20.save(Unknown Source)
      at com.jr.freedom.dao.UserDao.addNewUser(UserDao.java:50)
      at com.jr.freedom.user.UserService.registerNewUser(UserService.java:47)
      at com.jr.freedom.controllers.UserController.createNewAccount(UserController.java:57)
      at com.test.jr.freedom.controllers.UserControllerTest.testCreateNewAccount(UserControllerTest.java:61)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
      at java.lang.reflect.Method.invoke(Method.java:597)
      at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
      at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
      at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
      at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
      at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
      at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
      at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
      at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
      at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
      at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
      at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
      at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
      at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
      at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
      at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
      at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
      at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
      at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
      at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
      at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
      at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
  </code></pre>
  
  <p>it crashes when i invoke session.save(user);</p>