title: Null GrantedAuthority to get UserDetails on Spring Security
body: <p>This is my UserDetails service in spring security:</p>
  
  <pre><code>public class UserDetail implements UserDetailsService {
  
      @Autowired
      User_service user_service;
  
      @Override
      public UserDetails loadUserByUsername(String userId) throws UsernameNotFoundException {
          boolean enabled = true;
          boolean accountNonExpired = true;
          boolean credentialsNonExpired = true;
          boolean accountNonLocked = true; 
          com.domain.User user = user_service.findByUserName(userId);
          return new User(user.getUserId(), user.getPassword(), enabled,
                              accountNonExpired, credentialsNonExpired, 
                              accountNonLocked, this.getGrantedAuthorities(user));
      }
  
      public List&lt;GrantedAuthority&gt; getGrantedAuthorities(com.domain.User user) {
          List&lt;GrantedAuthority&gt; role_name = null;
          List&lt;Role&gt; roles = user.getRoles();
          try {
              for(Role role : roles) {
                  role_name.add(new GrantedAuthorityImpl(role.getName()));
              }
          } catch(Exception ex) {
              System.out.println(ex.toString());
          }
          return role_name;
      }
  
  }
  </code></pre>
  
  <p>And I am getting this exception:</p>
  
  <pre class="lang-none prettyprint-override"><code>org.springframework.security.authentication.InternalAuthenticationServiceException: Cannot  pass a null GrantedAuthority collection
  at   org.springframework.security.authentication.dao.DaoAuthenticationProvider.retrieveUser(DaoAuthenticationProvider.java:110)
  at org.springframework.security.authentication.dao.AbstractUserDetailsAuthenticationProvider.authenticate(AbstractUserDetailsAuthenticationProvider.java:132)
  at org.springframework.security.authentication.ProviderManager.authenticate(ProviderManager.java:156)
  at org.springframework.security.authentication.ProviderManager.authenticate(ProviderManager.java:177)
  at org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter.attemptAuthentication(UsernamePasswordAuthenticationFilter.java:94)
  at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:211)
  at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
  at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:110)
  at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
  at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:50)
  at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
  at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
  at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
  at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
  at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
  at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
  at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
  at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214)
  at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:316)
  at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
  at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
  at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
  at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
  at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
  at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:357)
  at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:260)
  at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:188)
  at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:191)
  at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:168)
  at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:189)
  at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
  at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:288)
  at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:206)
  at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:136)
  at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:114)
  at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
  at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:838)
  at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:113)
  at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:115)
  at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:55)
  at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:135)
  at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:564)
  at      org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:544)
  at java.lang.Thread.run(Thread.java:724)
  Caused by: java.lang.IllegalArgumentException: Cannot pass a null GrantedAuthority collection
  at org.springframework.util.Assert.notNull(Assert.java:112)
  at org.springframework.security.core.userdetails.User.sortAuthorities(User.java:146)
  at org.springframework.security.core.userdetails.User.&lt;init&gt;(User.java:108)
  </code></pre>
  
  <p>In <code>getGrantedAuthorities</code> method user object is found, I test it, but when I want to add the role name to GrantedAuthority list, it throws an exception "Cannot pass a null GrantedAuthority collection". Why GrantedAuthority returnning null?</p>
  
  <p>I am pretty sure that "user" object is not null, i checked it.</p>