title: Vim plugins declared in ftplugin do not work
body: <p>Gvim is behaving weird and I can't find the reason. I use Vundle, and all the plugins declared in my <code>.vimrc</code> are working fine. I declared some additional settings and plugins in <code>.vim/after/ftplugin/java.vim</code>.</p>
  
  <p>The mappings work fine, but the plugins do not work. If I choose a different file in my current gvim session, I get those error messages:</p>
  
  <pre><code>Error detected while processing function vundle#config#bundle[2]..&lt;SNR&gt;14_check_bundle_name:
  line 2:
  Vundle error: Name collision for Plugin Raimondi/delimitMate. Plugin Raimondi/delimitMate previously used the name "delimitMate". Skipping Plugin Raimondi/delimitMate.
  Vundle error: Name collision for Plugin artur-shaik/vim-javacomplete2...
  [comment: same error message for all plugins declared in the ftplugin]
  </code></pre>
  
  <p>I noticed, that if I run <code>:VundleInstall</code> the plugins are suddenly working (the error messages stay when I change the file, no plugins are installed when I use the command).</p>
  
  <p>Here is the beginning of my <code>.vimrc</code>:</p>
  
  <pre><code>syntax on
  set guifont=Inconsolata\ Medium\ 12
  set nocompatible
  set t_Co=256
  
  filetype off
  
  set rtp+=~/.vim/bundle/Vundle.vim
  call vundle#begin()
  
  " let Vundle manage Vundle, required
  Plugin 'VundleVim/Vundle.vim'
  
  "[comment: all plugins I use for every filetype]
  
  call vundle#end()            " required
  
  filetype plugin indent on
  </code></pre>
  
  <p>and this is my <code>java.vim</code> file:</p>
  
  <pre><code>filetype off
  "to automatically close brackets
  Plugin 'Raimondi/delimitMate'
  
  "omni-complete for Java
  Plugin 'artur-shaik/vim-javacomplete2'
  
  "use tab to navigate through insert completion
  Plugin 'ervandew/supertab'
  filetype plugin indent on
  
  "needed to make javacomplete2 working properly
  autocmd FileType java setlocal omnifunc=javacomplete#Complete
  </code></pre>
  
  <p>My OS is Ubuntu 16.04.</p>