# Java private variables in Ruby **URL:** \ **Category:** Rails\ **Created:** [April 16, 2008, 6:23pm UTC](https://www.ruby-forum.com/t/java-private-variables-in-ruby/134971 "2008-04-16T18:23:05Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![jlesleyball](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/48db29/32.png) [@jlesleyball](https://www.ruby-forum.com/u/jlesleyball)\ **Post date:** [April 16, 2008, 6:23pm UTC](https://www.ruby-forum.com/t/java-private-variables-in-ruby/134971/1 "2008-04-16T18:23:05Z")
Hi How would I achieve in Ruby what the following line does in Java?: private BufferedImage buf; I need a new BufferedImage, but I don’t want to initialize it yet. Thanks. Jennifer ---
**Author:** ![jlesleyball](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/48db29/32.png) [@jlesleyball](https://www.ruby-forum.com/u/jlesleyball)\ **Post date:** [April 16, 2008, 11:55pm UTC](https://www.ruby-forum.com/t/java-private-variables-in-ruby/134971/2 "2008-04-16T23:55:59Z")
On Apr 16, 5:22 pm, jlesleyball [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Hi > > How would I achieve in Ruby what the following line does in Java?: > > private BufferedImage buf; > > I need a new BufferedImage, but I don’t want to initialize it yet. You don’t need to declare things in advance in ruby, and typing is done dynamically so the ruby equivalent of that statement is basically an empty line 🙂 Fred ---
**Author:** ![jlesleyball](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/48db29/32.png) [@jlesleyball](https://www.ruby-forum.com/u/jlesleyball)\ **Post date:** [April 16, 2008, 11:57pm UTC](https://www.ruby-forum.com/t/java-private-variables-in-ruby/134971/3 "2008-04-16T23:57:09Z")
Hi Fred Thanks for answering my question again. I wanted to make it a method variable because I wanted to initialize it within the scope of a conditional loop as well as use it later on in the action method. So ,that’s why I thought I should declare it in the scope of the method. Is there something else I should be doing? JB On Apr 16, 1:20 pm, Frederick C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![jlesleyball](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/48db29/32.png) [@jlesleyball](https://www.ruby-forum.com/u/jlesleyball)\ **Post date:** [April 17, 2008, 9:16am UTC](https://www.ruby-forum.com/t/java-private-variables-in-ruby/134971/4 "2008-04-17T09:16:55Z")
On Apr 16, 10:45 pm, jlesleyball [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Hi Fred > > Thanks for answering my question again. I wanted to make it a method > variable because I wanted to initialize it within the scope of a > conditional loop as well as use it later on in the action method. > So ,that’s why I thought I should declare it in the scope of the > method. Is there something else I should be doing? You don’t need to declare variables in advance in ruby like you do in java (1 exception: if you create a variable inside a block it won’t be visible outside the block unless it already existed). If you really must buf = nil is all you need. Fred ---
**Author:** ![jlesleyball](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/48db29/32.png) [@jlesleyball](https://www.ruby-forum.com/u/jlesleyball)\ **Post date:** [April 17, 2008, 7:26am UTC](https://www.ruby-forum.com/t/java-private-variables-in-ruby/134971/5 "2008-04-17T07:26:19Z")
Attributes of a class are private by default. You have to use attr acessor ang getter to get access to them. [Http://www.rubyplus.org](Http://www.rubyplus.org) Free Ruby & Rails screencasts On Apr 16, 2008, at 1:20 PM, Frederick C. \ **Author:** ![jlesleyball](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/48db29/32.png) [@jlesleyball](https://www.ruby-forum.com/u/jlesleyball)\ **Post date:** [April 17, 2008, 12:29pm UTC](https://www.ruby-forum.com/t/java-private-variables-in-ruby/134971/6 "2008-04-17T12:29:39Z") Hi – On Wed, 16 Apr 2008, Bcp wrote: > Attributes of a class are private by default. You have to use attr > acessor ang getter to get access to them. Or, to put it slightly differently: An object’s instance variables are only visible to that object (i.e., only visible when ‘self’ is that object). If you expose an instance variable through getter and/or setter methods, then you’ve given your object an “attribute”, though there’s no real distinction between getter/setter methods that are implemented as simple wrappers around instance variables and those that aren’t. So instance variables are not, themselves, attributes; they’re just instance variables, and they can (but do not have to) participate in the creation of attributes. And there’s no language-level difference between an “attribute” and a getter and/or setter method in general (whether it uses instance variables or not). David – Rails training from David A. Black and Ruby Power and Light: ADVANCING WITH RAILS April 14-17 New York City INTRO TO RAILS June 9-12 Berlin ADVANCING WITH RAILS June 16-19 Berlin See [http://www.rubypal.com](http://www.rubypal.com) for details and updates! ---
**Author:** ![jlesleyball](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/48db29/32.png) [@jlesleyball](https://www.ruby-forum.com/u/jlesleyball)\ **Post date:** [April 17, 2008, 9:33am UTC](https://www.ruby-forum.com/t/java-private-variables-in-ruby/134971/7 "2008-04-17T09:33:04Z")
Yea one of the great parts about ruby is how its dynamically typed. If you want to declare a private variable accessible throughout the class use an instance variable: @buf = BufferedImage.new or in a local scope (not accessible outside the class): buf = … if you use an instance variable and want to access it outside the class (public interface): attr\_accessor :buf that automatically creates “getter” and “setter” for @buf which look like: def buf @buf end def buf=(value) @buf=value end