Ruby vs Java

Java vs Ruby : a quick and fair comparison
About the pros and cons of two popular programming languages

Jean-Baptiste Escoyez

Thursday 19 February 2009 1

Java vs Ruby : a quick and unfair comparison
About the elegance of Ruby
About the performance of Java
And how they can live together

Jean-Baptiste Escoyez


Ruby is interpreted, Java is compiled (before being interpreted)

>ruby my_program.rb >javac MyProgram.java
>java MyProgram

• Code can be loaded at runtime

• Code is easily accessible

• Difﬁcult to ship closed-source software

• Speed performance issues

Java vs Ruby : a quick and unfair comparison - Jean-Baptiste Escoyez


Ruby use dynamic typing

• Values have type, variables not def len(list)
x=0
list.each do |element|
• Decrease language complexity x += 1
end
end
- No type declaration
public static int len(List list)
- No type casting {
int x = 0;
Iterator listIterator =
• Increase ﬂexibility list.iterator();
while(listIterator.hasNext()){
x += 1;
• Errors appears at run-time }
}



Ruby syntax is terse

• Example 1 : The empty program

• Java

• Ruby




• Example 1 : The empty program

Class Test {
• Java public static void main(String[] args){}
}

• Ruby



• Example 2 : Basic getters and setters

Class Circle
• Java private Coordinate center, float radius;

public void setCenter(Coordinate center){
this.center = center;
}

public Coordinate getCenter(){
return center;
}

public void setRadius(float radius){
this.radius = radius;
}

public Coordinate getRadius(){
return radius;
}
}

class Circle
• Ruby attr_accessor :center, :radius
end



• Example 3 : Playing with lists

• Java List<String> languages = new LinkedList<String>();
languages.add(quot;Javaquot;);
languages.add(quot;Rubyquot;);
languages.add(quot;Pythonquot;);
languages.add(quot;Perlquot;);

• Ruby stuff = []
stuff << quot;Javaquot;, quot;Rubyquot;, quot;Pythonquot;

stuff = [quot;Javaquot;, quot;Rubyquot;, quot;Pythonquot;]

stuff = %w(Java Ruby Python)



Everything is an object (really everything!)
>3.times { puts quot;Hello FOSDEM !quot; }
=> Hello FOSDEM !
=> Hello FOSDEM !
=> Hello FOSDEM !

>self.class
=> Object

>1.class
=> Fixnum



Core classes can be extended easily

• A program which makes you crazy

class Fixnum
def +(i)
self - i
end
end

>1 + 1
=> 0



require ‘activesupport’

• Java if ( 1 % 2 == 1 ) System.err.println(quot;Odd!quot;)
=> Odd!

• Ruby if 11.odd?; print quot;Odd!
=> Odd!

• Java System.out.println(quot;Running time: quot; +
(3600 + 15 * 60 + 10) + quot;secondsquot;);

• Ruby puts quot;Running time:
#{1.hour + 15.minutes + 10.seconds} secondsquot;



Blocks

>find_integer([quot;aquot;,1, 4, 2,quot;9quot;,quot;cquot;]){|e| e.odd?}
=> 1

>def find_integer(array)
> for element in array
> if element.is_a?(Integer) && yield element
> return element
> end
> end
>end



Tidbits of metaprogramming

• Execution of given code

>eval(quot;puts 'Hi FOSDEM'quot;)
=> Hi FOSDEM

• Class extension

>speaker = Class.new
>speaker.class_eval do
> def hello_fosdem
> puts “Hello FOSDEM!”
> end
>end
>jean_baptiste = speaker.new
>jean_baptiste.hello_fosdem
=> “Hello FOSDEM!”



Going a bit further

• Deﬁning methods

>people = [quot;stevequot;, quot;aurelienquot;]
>speaker = Class.new
>speaker.class_eval do
> people.each do |person|
> define_method(quot;hello_#{person}quot;){
> puts quot;Hello #{person}quot;
> }
> end
>end
>jean_baptiste = speaker.new
>jean_baptiste.methods - Object.methods
=> [quot;hello_stevequot;, quot;hello_aurelienquot;]
>jean_baptiste.hello_steve
=> “Hello steve”



Summary

• Ruby is elegant

• Ruby is meaningful

• Ruby is ﬂexible

• Ruby is easily extensible

• Ruby is terse



Summary

• Ruby is elegant

• Ruby is meaningful

• Ruby is ﬂexible

• Ruby is easily extensible

• Ruby is terse

Is that all ???
What about Java?


Java win on performance ﬁeld

Source : http://shootout.alioth.debian.org/u32q/benchmark.php


On a business point of view

• Java is a well-known technology

• Lots of developments have been made with it

• Easy to ﬁnd experts

• Still not that much available Ruby developers

• Opensource fear



Solution: make them collaborate !

•JRuby : Demo



Conclusion

• Languages wars do not make sens

• Ruby is great for its terseness, readability and ﬂexibility

• Java is great for its performances

• JRuby makes them talk together

• Ruby + Java is a great combo



Thank you!
Questions?

References :
http://www.rubyrailways.com/sometimes-less-is-more/
http://www.javaworld.com/javaworld/jw-07-2006/jw-0717-ruby.html
http://shootout.alioth.debian.org/u32q/benchmark.php?test=all&lang=java&lang2=ruby
http://ola-bini.blogspot.com/2008/04/pragmatic-static-typing.html


Ruby vs Java

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