title: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'crudRepository'
body: <p>I work with a Spring boot project and I have the following entity class provided, </p>
  
  <pre><code>@Entity
  public class User {
  
      // form:hidden - hidden value
      @Id
      @GeneratedValue(strategy = GenerationType.IDENTITY)
      Integer id;
  
      // form:input - textbox
      @Column(name = "name", columnDefinition = "VARCHAR(30)", nullable = false)
      String name;
  
      // form:input - textbox
      @Column(name = "email", columnDefinition = "VARCHAR(50)", nullable = false)
      String email;
  
      // form:textarea - textarea
      @Column(name = "address", columnDefinition = "VARCHAR(255)", nullable = true)
      String address;
  
      // form:input - password
      @Column(name = "password", columnDefinition = "VARCHAR(20)", nullable = false)
      String password;
  
      // form:input - password
      String confirmPassword;
  
      // form:checkbox - single checkbox
      @Column(name = "newsletter", nullable = true)
      boolean newsletter;
  
      // form:checkboxes - multiple checkboxes
  //    @Column(columnDefinition = "VARCHAR(500)", nullable = false)
      @ElementCollection
      List&lt;String&gt; framework;
  
      // form:radiobutton - radio button
      @Column(name = "sex", columnDefinition = "VARCHAR(1)", nullable = true)
      String sex;
  
      // form:radiobuttons - radio button
      @Column(name = "number", nullable = true)
      Integer number;
  
      // form:select - form:option - dropdown - single select
      @Column(name = "", columnDefinition = "VARCHAR(10)", nullable = true)
      String country;
  
      // form:select - multiple=true - dropdown - multiple select
  //    @Column(columnDefinition = "VARCHAR(500)", nullable = true)
      @ElementCollection
      List&lt;String&gt; skill;
  
      //Check if this is for New of Update
      public boolean isNew() {
          return (this.id == null);
      }
  
  
      public Integer getId() {
          return id;
      }
  
      public void setId(Integer id) {
          this.id = id;
      }
  
      public String getName() {
          return name;
      }
  
      public void setName(String name) {
          this.name = name;
      }
  
      public String getEmail() {
          return email;
      }
  
      public void setEmail(String email) {
          this.email = email;
      }
  
      public String getAddress() {
          return address;
      }
  
      public void setAddress(String address) {
          this.address = address;
      }
  
      public String getPassword() {
          return password;
      }
  
      public void setPassword(String password) {
          this.password = password;
      }
  
      public String getConfirmPassword() {
          return confirmPassword;
      }
  
      public void setConfirmPassword(String confirmPassword) {
          this.confirmPassword = confirmPassword;
      }
  
      public boolean isNewsletter() {
          return newsletter;
      }
  
      public void setNewsletter(boolean newsletter) {
          this.newsletter = newsletter;
      }
  
      public List&lt;String&gt; getFramework() {
          return framework;
      }
  
      public void setFramework(List&lt;String&gt; framework) {
          this.framework = framework;
      }
  
      public String getSex() {
          return sex;
      }
  
      public void setSex(String sex) {
          this.sex = sex;
      }
  
      public Integer getNumber() {
          return number;
      }
  
      public void setNumber(Integer number) {
          this.number = number;
      }
  
      public String getCountry() {
          return country;
      }
  
      public void setCountry(String country) {
          this.country = country;
      }
  
      public List&lt;String&gt; getSkill() {
          return skill;
      }
  
      public void setSkill(List&lt;String&gt; skill) {
          this.skill = skill;
      }
  
      @Override
      public boolean equals(Object o) {
          if (this == o) return true;
          if (!(o instanceof User)) return false;
  
          User user = (User) o;
  
          if (isNewsletter() != user.isNewsletter()) return false;
          if (!getId().equals(user.getId())) return false;
          if (!getName().equals(user.getName())) return false;
          if (!getEmail().equals(user.getEmail())) return false;
          if (getAddress() != null ? !getAddress().equals(user.getAddress()) : user.getAddress() != null) return false;
          if (!getPassword().equals(user.getPassword())) return false;
          if (getConfirmPassword() != null ? !getConfirmPassword().equals(user.getConfirmPassword()) : user.getConfirmPassword() != null)
              return false;
          if (!getFramework().equals(user.getFramework())) return false;
          if (getSex() != null ? !getSex().equals(user.getSex()) : user.getSex() != null) return false;
          if (getNumber() != null ? !getNumber().equals(user.getNumber()) : user.getNumber() != null) return false;
          if (getCountry() != null ? !getCountry().equals(user.getCountry()) : user.getCountry() != null) return false;
          return getSkill() != null ? getSkill().equals(user.getSkill()) : user.getSkill() == null;
      }
  
      @Override
      public int hashCode() {
  
          int result = getId().hashCode();
  
          result = 31 * result + getName().hashCode();
          result = 31 * result + getEmail().hashCode();
          result = 31 * result + (getAddress() != null ? getAddress().hashCode() : 0);
          result = 31 * result + getPassword().hashCode();
          result = 31 * result + (getConfirmPassword() != null ? getConfirmPassword().hashCode() : 0);
          result = 31 * result + (isNewsletter() ? 1 : 0);
          result = 31 * result + getFramework().hashCode();
          result = 31 * result + (getSex() != null ? getSex().hashCode() : 0);
          result = 31 * result + (getNumber() != null ? getNumber().hashCode() : 0);
          result = 31 * result + (getCountry() != null ? getCountry().hashCode() : 0);
          result = 31 * result + (getSkill() != null ? getSkill().hashCode() : 0);
          return result;
      }
  }
  </code></pre>
  
  <p>I would like to write some customized operations and tried to define the interfaces in that respect. The repository interfaces are provided below, </p>
  
  <pre><code>public interface CrudRepository&lt;T, ID extends Serializable&gt;
          extends Repository&lt;T, ID&gt; {
  
      &lt;S extends T&gt; S save(S entity);
  
      T findOne(ID primaryKey);
  
      Iterable&lt;T&gt; findAll();
  
      Long count();
  
      void delete(T entity);
  
      boolean exists(ID primaryKey);
  
      // … more functionality omitted.
  }
  </code></pre>
  
  <p>This interface extends the previously provided interface, </p>
  
  <pre><code>@Repository
  public interface IUserRepository extends CrudRepository&lt;User, Long&gt;{
  
  }
  </code></pre>
  
  <p>While I compile the program, I get the following error, </p>
  
  <pre><code>Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'crudRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class java.lang.Object
  </code></pre>
  
  <p>What is the issue here?</p>
  
  <p><code>Updated</code></p>
  
  <p>The <code>Spring Boot</code> Application class is, </p>
  
  <pre><code>@SpringBootApplication
  public class WebApplication extends SpringBootServletInitializer {
  
      @Override
      protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
          return application.sources(WebApplication.class);
      }
  
      public static void main(String[] args) throws Exception {
          SpringApplication.run(WebApplication.class, args);
      }
  }
  </code></pre>