unzip -d #{jce_tmp} -o #{download_path} might be cleaner than the "cd".  

or maybe create dir separately and use bash :cwd attribute:
```ruby
directory "#{jce_tmp}" do
  action :create
  not_if ...
end

bash 'unzip-jce-zipfile' do
  cwd #{jce_tmp}
  code <<-CODE
  unzip -o #{download_path}
  CODE
  not_if ...
end
```