# ActionController : Exception caught

**URL:** <https://www.ruby-forum.com/t/actioncontroller-exception-caught/162202>\
**Category:** Rails\
**Created:** [March 6, 2009, 6:18pm UTC](https://www.ruby-forum.com/t/actioncontroller-exception-caught/162202 "2009-03-06T18:18:39Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![intern\_ruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/dc4da7/32.png) [@intern\_ruby](https://www.ruby-forum.com/u/intern_ruby)\
**Post date:** [March 6, 2009, 6:18pm UTC](https://www.ruby-forum.com/t/actioncontroller-exception-caught/162202/1 "2009-03-06T18:18:39Z")

</div>

I am running MySql 5.0.77 and Ruby 2.2.2 I am able to add records -  
howeevr when I start the server, I am geting following error message.  
Please help. I am anot able to see the GUI.

ArgumentError in UsersController#index  
NULL pointer given  
RAILS\_ROOT: C:/workspace/testapp

Application Trace | Framework Trace | Full Trace  
(eval):3:in `each_hash' (eval):3:in`all\_hashes’  
app/controllers/users\_controller.rb:3:in `index' c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/connection_adapters/mysql_adapter.rb:564:in`select’  
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/connection\_adapters/abstract/database\_statements.rb:7:in  
`select_all_without_query_cache' c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/connection_adapters/abstract/query_cache.rb:60:in`select\_all’  
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/connection\_adapters/abstract/query\_cache.rb:81:in  
`cache_sql' c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/connection_adapters/abstract/query_cache.rb:60:in`select\_all’  
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/base.rb:635:in  
`find_by_sql' c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/base.rb:1490:in`find\_every’  
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/base.rb:589:in  
`find' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:1253:in`send’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/base.rb:1253:in  
`perform_action_without_filters' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/filters.rb:617:in`call\_filters’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/filters.rb:610:in  
`perform_action_without_benchmark' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:68:in`perform\_action\_without\_rescue’  
c:/ruby/lib/ruby/1.8/benchmark.rb:293:in `measure' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:68:in`perform\_action\_without\_rescue’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/rescue.rb:136:in  
`perform_action_without_caching' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/caching/sql_cache.rb:13:in`perform\_action’  
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/connection\_adapters/abstract/query\_cache.rb:34:in  
`cache' c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/query_cache.rb:8:in`cache’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/caching/sql\_cache.rb:12:in  
`perform_action' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:524:in`send’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/base.rb:524:in  
`process_without_filters' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/filters.rb:606:in`process\_without\_session\_management\_support’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/session\_management.rb:134:in  
`process' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:392:in`process’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/dispatcher.rb:183:in  
`handle_request' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:110:in`dispatch\_unlocked’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/dispatcher.rb:123:in  
`dispatch' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:122:in`synchronize’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/dispatcher.rb:122:in  
`dispatch' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:132:in`dispatch\_cgi’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/dispatcher.rb:39:in  
`dispatch' c:/ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/webrick_server.rb:103:in`handle\_dispatch’  
c:/ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/webrick\_server.rb:74:in  
`service' c:/ruby/lib/ruby/1.8/webrick/httpserver.rb:104:in`service’  
c:/ruby/lib/ruby/1.8/webrick/httpserver.rb:65:in `run' c:/ruby/lib/ruby/1.8/webrick/server.rb:173:in`start\_thread’  
c:/ruby/lib/ruby/1.8/webrick/server.rb:162:in `start' c:/ruby/lib/ruby/1.8/webrick/server.rb:162:in`start\_thread’  
c:/ruby/lib/ruby/1.8/webrick/server.rb:95:in `start' c:/ruby/lib/ruby/1.8/webrick/server.rb:92:in`each’  
c:/ruby/lib/ruby/1.8/webrick/server.rb:92:in `start' c:/ruby/lib/ruby/1.8/webrick/server.rb:23:in`start’  
c:/ruby/lib/ruby/1.8/webrick/server.rb:82:in `start' c:/ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/webrick_server.rb:60:in`dispatch’  
c:/ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/commands/servers/webrick.rb:66  
c:/ruby/lib/ruby/site\_ruby/1.8/rubygems/custom\_require.rb:31:in  
`gem_original_require' c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in`require’  
c:/ruby/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active\_support/dependencies.rb:153:in  
`require' c:/ruby/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in`new\_constants\_in’  
c:/ruby/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active\_support/dependencies.rb:153:in  
`require' c:/ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/commands/server.rb:49 c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in`gem\_original\_require’  
c:/ruby/lib/ruby/site\_ruby/1.8/rubygems/custom\_require.rb:31:in  
`require' script/server:3 (eval):3:in`each\_hash’  
(eval):3:in `all_hashes' c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/connection_adapters/mysql_adapter.rb:564:in`select’  
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/connection\_adapters/abstract/database\_statements.rb:7:in  
`select_all_without_query_cache' c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/connection_adapters/abstract/query_cache.rb:60:in`select\_all’  
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/connection\_adapters/abstract/query\_cache.rb:81:in  
`cache_sql' c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/connection_adapters/abstract/query_cache.rb:60:in`select\_all’  
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/base.rb:635:in  
`find_by_sql' c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/base.rb:1490:in`find\_every’  
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/base.rb:589:in  
`find' app/controllers/users_controller.rb:3:in`index’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/base.rb:1253:in  
`send' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:1253:in`perform\_action\_without\_filters’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/filters.rb:617:in  
`call_filters' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/filters.rb:610:in`perform\_action\_without\_benchmark’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/benchmarking.rb:68:in  
`perform_action_without_rescue' c:/ruby/lib/ruby/1.8/benchmark.rb:293:in`measure’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/benchmarking.rb:68:in  
`perform_action_without_rescue' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/rescue.rb:136:in`perform\_action\_without\_caching’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/caching/sql\_cache.rb:13:in  
`perform_action' c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in`cache’  
c:/ruby/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active\_record/query\_cache.rb:8:in  
`cache' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/caching/sql_cache.rb:12:in`perform\_action’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/base.rb:524:in  
`send' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:524:in`process\_without\_filters’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/filters.rb:606:in  
`process_without_session_management_support' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/session_management.rb:134:in`process’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/base.rb:392:in  
`process' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:183:in`handle\_request’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/dispatcher.rb:110:in  
`dispatch_unlocked' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:123:in`dispatch’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/dispatcher.rb:122:in  
`synchronize' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:122:in`dispatch’  
c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action\_controller/dispatcher.rb:132:in  
`dispatch_cgi' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.2.2/lib/action_controller/dispatcher.rb:39:in`dispatch’  
c:/ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/webrick\_server.rb:103:in  
`handle_dispatch' c:/ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/webrick_server.rb:74:in`service’  
c:/ruby/lib/ruby/1.8/webrick/httpserver.rb:104:in `service' c:/ruby/lib/ruby/1.8/webrick/httpserver.rb:65:in`run’  
c:/ruby/lib/ruby/1.8/webrick/server.rb:173:in `start_thread' c:/ruby/lib/ruby/1.8/webrick/server.rb:162:in`start’  
c:/ruby/lib/ruby/1.8/webrick/server.rb:162:in `start_thread' c:/ruby/lib/ruby/1.8/webrick/server.rb:95:in`start’  
c:/ruby/lib/ruby/1.8/webrick/server.rb:92:in `each' c:/ruby/lib/ruby/1.8/webrick/server.rb:92:in`start’  
c:/ruby/lib/ruby/1.8/webrick/server.rb:23:in `start' c:/ruby/lib/ruby/1.8/webrick/server.rb:82:in`start’  
c:/ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/webrick\_server.rb:60:in  
`dispatch' c:/ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/commands/servers/webrick.rb:66 c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in`gem\_original\_require’  
c:/ruby/lib/ruby/site\_ruby/1.8/rubygems/custom\_require.rb:31:in  
`require' c:/ruby/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in`require’  
c:/ruby/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active\_support/dependencies.rb:521:in  
`new_constants_in' c:/ruby/lib/ruby/gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in`require’  
c:/ruby/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/commands/server.rb:49  
c:/ruby/lib/ruby/site\_ruby/1.8/rubygems/custom\_require.rb:31:in  
`gem_original_require' c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in`require’  
script/server:3

---

<div class="post-metadata">

**Author:** ![intern\_ruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/dc4da7/32.png) [@intern\_ruby](https://www.ruby-forum.com/u/intern_ruby)\
**Post date:** [March 6, 2009, 10:11pm UTC](https://www.ruby-forum.com/t/actioncontroller-exception-caught/162202/2 "2009-03-06T22:11:55Z")

</div>

Hi Yati,

On Fri, 2009-03-06 at 18:18 +0100, Yati Tandon wrote:

> I am running MySql 5.0.77 and Ruby 2.2.2 I am able to add records -  
> howeevr when I start the server, I am geting following error message.  
> Please help. I am anot able to see the GUI.

I’m guessing you’re new to RoR and haven’t learned how to read the error  
messages. Hope this helps.

> ArgumentError in UsersController#index

The error is in users\_controller.rb in the index method.

> NULL pointer given

A NULL pointer is being passed to to something

> RAILS\_ROOT: C:/workspace/testapp

in the Rails application named ‘testapp’

> Application Trace | Framework Trace | Full Trace  
> (eval):3:in `each_hash' (eval):3:in`all\_hashes’

ah… it’s a null pointer in a hash, which probably means it involves a  
key rather than a value.

> app/controllers/users\_controller.rb:3:in `index’

The specific problem can be found in line 3 of users\_controller.rb which  
is inside the index method.

The stack trace past here is, for your purposes, typically noise, not  
signal.

Without seeing the actual code, it’s not possible to nail it down  
further than that. Post the code if you need more help.

Best regards,  
Bill

---

<div class="post-metadata">

**Author:** ![intern\_ruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/dc4da7/32.png) [@intern\_ruby](https://www.ruby-forum.com/u/intern_ruby)\
**Post date:** [March 7, 2009, 5:32pm UTC](https://www.ruby-forum.com/t/actioncontroller-exception-caught/162202/3 "2009-03-07T17:32:08Z")

</div>

Thanks Bill for your reply. Yes, I am new to ROR. Please tell me where  
am I wrong. I have attached code.

Thanks,  
Yati

---

<div class="post-metadata">

**Author:** ![intern\_ruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/dc4da7/32.png) [@intern\_ruby](https://www.ruby-forum.com/u/intern_ruby)\
**Post date:** [March 9, 2009, 5:05pm UTC](https://www.ruby-forum.com/t/actioncontroller-exception-caught/162202/4 "2009-03-09T17:05:13Z")

</div>

hey Bill,

My index page is still not getting displayed. Please have a look on the  
code. I am getting default page of Ruby server getting displayed. Pls  
help. I will appreciate that.

Thanks.

---

<div class="post-metadata">

**Author:** ![intern\_ruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/dc4da7/32.png) [@intern\_ruby](https://www.ruby-forum.com/u/intern_ruby)\
**Post date:** [March 8, 2009, 5:46am UTC](https://www.ruby-forum.com/t/actioncontroller-exception-caught/162202/5 "2009-03-08T05:46:33Z")

</div>

On Sat, 2009-03-07 at 17:32 +0100, Intern ruby wrote:

> Thanks Bill for your reply. Yes, I am new to ROR. Please tell me where  
> am I wrong. I have attached code.

It’s more typical to simply copy the relevant pieces of code than to  
zip an entire project. However, the error message you cited in your  
initial post…

ArgumentError in UsersController#index  
NULL pointer given

probably wasn’t generated by the code you attached inasmuch as it didn’t  
contain a users\_controller.rb file. Back up and start over would be my  
best advice.

HTH,  
Bill