# Ten Things Every Java Programmer Should Know About Ruby **URL:** \ **Category:** ruby-talk\ **Created:** [27 January 2005 21:54 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086 "2005-01-27T21:54:54Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![E\_S](https://avatars.discourse-cdn.com/v4/letter/e/3be4f8/32.png) [@E\_S](https://rubytalk.org/u/E_S)\ **Post date:** [27 January 2005 21:54 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/1 "2005-01-27T21:54:54Z")
> Lähettäjä: "Jim Weirich" \ > Aihe: Ten Things Every Java Programmer Should Know About Ruby > > We will be introducing Ruby to our XP Users group in Cincinnati next week. > I thought it would be fun to create a list of "Ten Things Every Java > Programmer Should Know About Ruby" to help the transition. I've got a > number of things in my head, but would love to hear ideas from the mailing > list. > > So go ahead and submit your ideas. What things should a Java programmer > be aware of when starting out in Ruby? Here's the list so far: > **···** > > ------------------------------------------------------------------- > Ruby classes are Objects (therefore String.new, not new String()) > Everything is an Object > Compared to Java, XML is agile. Compared to Ruby, XML is Heavy. > Ruby does not have type casting. > Don't worry about interfaces, enjoy Duck Typing. > No method overloading > Enjoy closures and blocks > Don't worry about early performance optimization > Web-development is possible with other languages besides Java. > Ruby has O/R mappers, so find your Ruby "hibernate", but drop any preconceptions. > Ruby has MVC and OO programming and libraries, but drop any preconceptions. > Ruby is a language to be used everywhere. You use it even in templates. No need for "Velocity/JSP." > Ruby is not a Silver Bullet, unlike Java, right? 🙂 > In Ruby data is strongly typed, but variables are \*not\* > you can have variable number of parameters, and multiple return values > Once you start coding Ruby, going back to Java is painful. > "." (dot) is a method call operator. "::" (colon-colon) is a scope operator. > Java static methods do not (quite) translate to Ruby class methods. > CamelCase for class names, names\_with\_underscores for methods and variables. > Everything is an expression. > That you can write Ruby in Java ([http://jruby.sourceforge.net](http://jruby.sourceforge.net)) > stop writing so much code > @local\_variable, $global\_variable, Constants, (and @@class\_variables) > ri is your friend. irb is your other friend. > Reflection in Ruby is much easier than in Java, and more deeply into the language than the java.lang.reflect tack-on. > eval > the builtin classes are much faster because they're written in C and not Ruby > Boolean methods end in ?. Dangerous methods end in ! > Avoid external utility classes > Use class methods to define pseudo-compile directives > You probably don't need Factories > Enumerable is your friend > No external configuration files > method\_missing > Typing is the enemy > C extensions/wrappers are \*much\* easier in Ruby than JNI interfaces in Java > Ruby classes are always "open". > Singleton methods > no semi-colons, optional parenthesis > Ruby packaging vs Java packaging > you can use string interpolation, ex: "x: #{@myvar}" instead of having to say "x:" myvar' > ruby has multiple inheritance through mixins (this is sooo nice to have) > ruby has shortcuts for accessor methods which reduces alot of redundant coding in java > writing code in ruby, can improve the code you write in java > ----------------------------------------------------------------- > > If there's one thing to be said it's that these are clearly items > from current users and I'm afraid they're maybe too specific. To > summarize some of these points: > > \* Ruby is pure OO. Everything is an object. 'Hello' is an object, > 1 is an object, Class is an object and so on. Ruby's OO is structured > in such a way that it assists you in writing good OO code and allows > you to think about the problem in a more natural manner. Multiple > inheritance is allowed through mixins. > > \* Ruby is dynamic. You can add, remove and modify objects, classes and > methods at runtime, and that also applies to built-in and standard > classes. Ever wanted to add a method to class String? Now you can. > Ruby has extensive reflection capabilities. One could go as far as > to say that Java doesn't have reflection. > > \* Ruby is agile, perfectly suited for XP. It's easy to prototype in > but surprisingly even such fast code ends up being easy to build on. > Coding time decreases dramatically and bugs are infrequent. > > \* Ruby is strongly typed, not statically typed. Each variable has a > strict type that it represents, but a type declaration is not needed > in e.g. method definitions. The result of this is that you don't treat > and classify objects based on what their type is, you do it based on > what that particular object can do. This concept is called 'duck > typing': "If it walks like a duck and it quacks like a duck, it's a > duck". > > \* Ruby offers many, many syntactic enhancements to make your job > easier. You write very concise, clear and elegant code without > sacrificing functionality. Indeed, you gain some. One of the most > favourite features of Ruby programmers are code blocks, which are > often used in place of iterators. > > \* Ruby is plenty fast for everyday applications. If, after you've > written a program, you profile it and find a certain bottleneck, > you can easily drop down to C to rewrite that portion. This is usually > not necessary. > > \* Ruby can be extended with C very easily. The API is clean and > easy compared to JNI, Python or Perl. Extensions are usually used > to bridge existing libraries to Ruby. > > When's this meeting, anyway? 🙂 > > > -- Jim Weirich jim@weirichhouse.org [http://onestepback.org](http://onestepback.org) > > E ---
**Author:** ![Ben\_Giddings1](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@Ben\_Giddings1](https://rubytalk.org/u/Ben_Giddings1)\ **Post date:** [27 January 2005 22:38 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/2 "2005-01-27T22:38:20Z")
E S wrote: > Here's the list so far: > ------------------------------------------------------------------- > Ruby classes are Objects (therefore String.new, not new String()) Everything is an Object I'd emphasize this for Java ppl. Many of them think that Java is fully object oriented, but they then have to deal with the problems if "int" vs. Integer. I'd make this fully clear to them by using one of the really cool things like: 5.times { puts "Everything is an object!" } > Everything is an expression. A great example of this is: language = case(name)             when "John", "Jane", "Mike"               "English"             when "Yukihiro", "Maiko"               "Japanese"             else               "Unknown"             end > ri is your friend. irb is your other friend. I'd say irb is your best friend. ri is cool and all, but nothing beats being able to fire up irb and see for yourself what happens. > method\_missing Show off the roman numerals example from the pickaxe for this one, that's always impressive. > ruby has shortcuts for accessor methods which reduces alot of redundant coding in java And, ruby has no public members, so all access \*must\* be through accessors. That's a major deal for Java ppl, who are used to having to have a "foo" member variable, and then a getFoo() and setFoo() method. Start with the default accessor, then if/when needed, add bounds checking and whatever else you'd like. Ben ---
**Author:** ![Yohanes\_Santoso1](https://avatars.discourse-cdn.com/v4/letter/y/ccd318/32.png) [@Yohanes\_Santoso1](https://rubytalk.org/u/Yohanes_Santoso1)\ **Post date:** [28 January 2005 03:04 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/3 "2005-01-28T03:04:45Z")
E S \ writes: > Everything is an Object I have never liked this over-generalised slogan. Without qualifying it, then the sentence 'expression is an Object' would be true, yet that is not true. It should be qualified as: every object is an Object. The word 'object' there has two senses. The first and obvious one is instances of Object or its descendants. The second meaning is data entity. > \* Ruby is pure OO. I also have never liked this proclamation as everyone has their own definitions of what OO is. This proclamation is worth not much more than proclaiming the assembly language is 'pure OO'. YS. ---
**Author:** ![Navindra\_Umanee](https://avatars.discourse-cdn.com/v4/letter/n/d78d45/32.png) [@Navindra\_Umanee](https://rubytalk.org/u/Navindra_Umanee)\ **Post date:** [29 January 2005 17:13 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/4 "2005-01-29T17:13:53Z")
What is the point of strong typing then? Thanks, Navin. > **···** > > E S \ wrote: > > > \* Ruby is strongly typed, not statically typed. Each variable has a > > strict type that it represents, but a type declaration is not needed > > in e.g. method definitions. The result of this is that you don't treat > > and classify objects based on what their type is, you do it based on > > what that particular object can do. This concept is called 'duck > > typing': "If it walks like a duck and it quacks like a duck, it's a > > duck". ---
**Author:** ![James\_Britt6](https://avatars.discourse-cdn.com/v4/letter/j/a87d85/32.png) [@James\_Britt6](https://rubytalk.org/u/James_Britt6)\ **Post date:** [28 January 2005 03:30 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/5 "2005-01-28T03:30:19Z")
Yohanes Santoso wrote: > E S \ writes: > > > Everything is an Object > > I have never liked this over-generalised slogan. Without qualifying > it, then the sentence 'expression is an Object' would be true, yet > that is not true. > > It should be qualified as: every object is an Object. The word > 'object' there has two senses. The first and obvious one is instances > of Object or its descendants. The second meaning is data entity. > > > \* Ruby is pure OO. > > I also have never liked this proclamation as everyone has their own > definitions of what OO is. This proclamation is worth not much more > than proclaiming the assembly language is 'pure OO'. Certain descriptions are more useful for catchy buzz phrases than technical discourse. If you are addressing a group of developers, Show, Don't Tell might be a good approach. James ---
**Author:** ![Bill\_Kelly](https://avatars.discourse-cdn.com/v4/letter/b/cc9497/32.png) [@Bill\_Kelly](https://rubytalk.org/u/Bill_Kelly)\ **Post date:** [28 January 2005 04:20 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/6 "2005-01-28T04:20:00Z")
> E S \ writes: > > \> Everything is an Object > > I have never liked this over-generalised slogan. Without qualifying > it, then the sentence 'expression is an Object' would be true, yet > that is not true. > > It should be qualified as: every object is an Object. The word > 'object' there has two senses. The first and obvious one is instances > of Object or its descendants. The second meaning is data entity. While, "Everything is an Object" may be an exxageration, I think there's enough truth to it for it not to be a meaningless statement. In how many languages that claim to be OO are all data types, even integers, floats, and strings, Objects? And in how many are Classes themselves first-class Objects? In my admittedly limited experience, (Perl, Python, C++, Objective C, Java, Smalltalk), just one language. Oh, and ruby. Two languages. 🙂 > \> \* Ruby is pure OO. > > I also have never liked this proclamation as everyone has their own > definitions of what OO is. This proclamation is worth not much more > than proclaiming the assembly language is 'pure OO'. Clearly[1], a language is OO if Alan Kay says it is. 🙂 Since ruby borrows significantly from Smalltalk's object model, there's a good chance ruby is OO, too. \ [1] [http://c2.com/cgi/wiki?HeInventedTheTerm](http://c2.com/cgi/wiki?HeInventedTheTerm) Happy Rubying, Regards, Bill > **···** > > From: "Yohanes Santoso" \ ---
**Author:** ![Lothar\_Scholz2](https://avatars.discourse-cdn.com/v4/letter/l/f14d63/32.png) [@Lothar\_Scholz2](https://rubytalk.org/u/Lothar_Scholz2)\ **Post date:** [29 January 2005 17:33 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/7 "2005-01-29T17:33:48Z")
Hello Navindra, > > \* Ruby is strongly typed, not statically typed. Each variable has a > > strict type that it represents, but a type declaration is not needed > > in e.g. method definitions. The result of this is that you don't treat > > and classify objects based on what their type is, you do it based on > > what that particular object can do. This concept is called 'duck > > typing': "If it walks like a duck and it quacks like a duck, it's a > > duck". > What is the point of strong typing then? Good question. Thinking a little bit about it i would say that in fact then ruby is untyped not strong typed. It's just that out of history with untyped you mean that you can do byte operations in the address space with pointer arithmetics or other ultra low level operations. And the consequences in the history was an uncontrolled crash now it is a controlled crash (aka exception). If i can add and remove methods and instance variables whenever i want, how is this diffent from a C typecast ? > **···** > > > E S \ wrote: > > -- > Best regards, emailto: scholz at scriptolutions dot com > Lothar Scholz [http://www.ruby-ide.com](http://www.ruby-ide.com) > CTO Scriptolutions Ruby, PHP, Python IDE 's ---
**Author:** ![PA1](https://avatars.discourse-cdn.com/v4/letter/p/71c47a/32.png) [@PA1](https://rubytalk.org/u/PA1)\ **Post date:** [29 January 2005 18:07 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/8 "2005-01-29T18:07:24Z")
Pig aPig = Pig.new() Bird aBird = Bird.new() aFlyingPig = (Bird) aPig Doesn't make it so. Cheers > **···** > > On Jan 29, 2005, at 18:13, Navindra Umanee wrote: > > > What is the point of strong typing then? > > -- > PA, Onnay Equitursay > [http://alt.textdrive.com/](http://alt.textdrive.com/) ---
**Author:** ![Navindra\_Umanee](https://avatars.discourse-cdn.com/v4/letter/n/d78d45/32.png) [@Navindra\_Umanee](https://rubytalk.org/u/Navindra_Umanee)\ **Post date:** [29 January 2005 18:22 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/9 "2005-01-29T18:22:21Z")
In Ruby, objects pass for different types all the time. In my own recent Ruby code I've mistakenly passed in the wrong types but didn't notice because the types responded to the same methods. Even though the type didn't change, effectively the problem and bug shadowing was identical to the case you describe. Cheers, Navin. > **···** > > Florian Gross \ wrote: > > > Not having your Objects changing types all the time without you > > noticing. If you forget to initialize a field in PHP it will be > > converted to zero or an empty String if necessary thus shadowing your > > bug. Strong typing usually is a requirement for languages where OOP > > works well. ---
**Author:** ![Lothar\_Scholz2](https://avatars.discourse-cdn.com/v4/letter/l/f14d63/32.png) [@Lothar\_Scholz2](https://rubytalk.org/u/Lothar_Scholz2)\ **Post date:** [29 January 2005 18:23 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/10 "2005-01-29T18:23:40Z")
Hello PA, > **···** > > > On Jan 29, 2005, at 18:13, Navindra Umanee wrote: > > > > What is the point of strong typing then? > > > Pig aPig = Pig.new() > > Bird aBird = Bird.new() > > > aFlyingPig = (Bird) aPig > > > Doesn't make it so. > > A Bird is a Bird if it can "drink" and if it can "eat". > Then isn't the typecast maybe correct ? > > -- > Best regards, emailto: scholz at scriptolutions dot com > Lothar Scholz [http://www.ruby-ide.com](http://www.ruby-ide.com) > CTO Scriptolutions Ruby, PHP, Python IDE 's ---
**Author:** ![Navindra\_Umanee](https://avatars.discourse-cdn.com/v4/letter/n/d78d45/32.png) [@Navindra\_Umanee](https://rubytalk.org/u/Navindra_Umanee)\ **Post date:** [29 January 2005 18:27 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/11 "2005-01-29T18:27:55Z")
This looks more like Java than Ruby... I don't see your point. In Ruby you would get: class Pig def what\_am\_i p "pig" end end class Bird def what\_am\_i p "bird" end end pig = Pig.new bird = Bird.new method\_expecting\_pig\_but\_given\_bird(bird) Makes it so. Cheers, Navin. > **···** > > PA \ wrote: > > > On Jan 29, 2005, at 18:13, Navindra Umanee wrote: > > > > \> What is the point of strong typing then? > > > > Pig aPig = Pig.new() > > Bird aBird = Bird.new() > > > > aFlyingPig = (Bird) aPig > > > > Doesn't make it so. ---
**Author:** ![Joao\_Pedrosa](https://avatars.discourse-cdn.com/v4/letter/j/e56c9b/32.png) [@Joao\_Pedrosa](https://rubytalk.org/u/Joao_Pedrosa)\ **Post date:** [29 January 2005 18:47 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/12 "2005-01-29T18:47:40Z")
Hi, > \> Not having your Objects changing types all the time without you > \> noticing. If you forget to initialize a field in PHP it will be > \> converted to zero or an empty String if necessary thus shadowing your > \> bug. Strong typing usually is a requirement for languages where OOP > \> works well. > > In Ruby, objects pass for different types all the time. In my own > recent Ruby code I've mistakenly passed in the wrong types but didn't > notice because the types responded to the same methods. > > Even though the type didn't change, effectively the problem and bug > shadowing was identical to the case you describe. Yes, because the type is not checked for most of the operations. Well, we work on high-level objects, not with memory pointers. The high-level objects get created and recreated on demand by the language, so one change in a determined variable won't break the code somewhere else, as it probably is working on a local copy of the object (the data and methods, not the memory pointer.) When objects get "passed by value" it helps a lot the general stability of the system. That's why even in Java you pass by value. Though when you want a bullet proof library, you need extra-work to avoid the user from messing up with the internal code (in Java.) In Ruby, we are freer from the "static typing" checks, and as freedom is something (generally,) good, we have more features which allow us to be freer than with other languages. This article talks about languages and tools: [http://osteele.com/archives/2004/11/ides](http://osteele.com/archives/2004/11/ides) So yeah, we don't have everything that other languages have. It's good or bad depending if you require those features/tools. The problem is that we don't have a definitive answer to whether there is a God, as well as we don't have a definitive answer on whether dynamic languages (that are not Smalltalk) can be as tool enabled as the static typed languages. Maybe not. Can we do ok even without certain tools? Maybe, depending on some factors. Our memory allocated "objects" have strong types, but they aren't enforced on the operations, because we don't add types to our coding, like in Java. If Ruby was to be more like Java, it would lose its "sparkness." If type could be infered and pre-checked, then at least it would be an improvement over Java's approach. And any investment on Ruby should not try to take it over from the community. 🙂 Cheers, Joao > **···** > > On Sun, 30 Jan 2005 03:22:21 +0900, Navindra Umanee \ wrote: > > > Florian Gross \ wrote: ---
**Author:** ![gabriele\_renzi](https://avatars.discourse-cdn.com/v4/letter/g/e19b73/32.png) [@gabriele\_renzi](https://rubytalk.org/u/gabriele_renzi)\ **Post date:** [30 January 2005 01:15 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/13 "2005-01-30T01:15:49Z")
Navindra Umanee ha scritto: > > Not having your Objects changing types all the time without you noticing. If you forget to initialize a field in PHP it will be converted to zero or an empty String if necessary thus shadowing your bug. Strong typing usually is a requirement for languages where OOP works well. > > In Ruby, objects pass for different types all the time. In my own > recent Ruby code I've mistakenly passed in the wrong types but didn't > notice because the types responded to the same methods. > > Even though the type didn't change, effectively the problem and bug > shadowing was identical to the case you describe. not quite the same. compare: method sum(a,b)   return a+b strongly typed language: a='yo' b=2 sum(a,b) #error weak typed: a='yo' b=2 method sum(a,b) # 2 with 'yo' converted to 0? "yo2" with 2 stringified? the former has much less potential to hide an error. > **···** > > > Florian Gross \ wrote: ---
**Author:** ![PA1](https://avatars.discourse-cdn.com/v4/letter/p/71c47a/32.png) [@PA1](https://rubytalk.org/u/PA1)\ **Post date:** [29 January 2005 18:29 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/14 "2005-01-29T18:29:53Z")
It could indeed be perfectly correct if Pig is derived from Bird. Then you could easily have flying pigs. I would love to see such taxonomy though 8^) Cheers > **···** > > On Jan 29, 2005, at 19:23, Lothar Scholz wrote: > > > A Bird is a Bird if it can "drink" and if it can "eat". > > Then isn't the typecast maybe correct ? > > -- > PA, Onnay Equitursay > [http://alt.textdrive.com/](http://alt.textdrive.com/) ---
**Author:** ![PA1](https://avatars.discourse-cdn.com/v4/letter/p/71c47a/32.png) [@PA1](https://rubytalk.org/u/PA1)\ **Post date:** [29 January 2005 18:40 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/15 "2005-01-29T18:40:50Z")
Sorry. Forgot to reboot in Ruby mode: aMethodExceptingToFlyABirdButGivenAPigInstead( aPig ) And what would happen to this mythical flying pig now? aPig.fly()? EXC\_BAD\_ACCESS (aka method\_missing). Cheers > **···** > > On Jan 29, 2005, at 19:27, Navindra Umanee wrote: > > > This looks more like Java than Ruby... I don't see your point. > > -- > PA, Onnay Equitursay > [http://alt.textdrive.com/](http://alt.textdrive.com/) ---
**Author:** ![Gavin\_Kistner2](https://avatars.discourse-cdn.com/v4/letter/g/b9e5f3/32.png) [@Gavin\_Kistner2](https://rubytalk.org/u/Gavin_Kistner2)\ **Post date:** [31 January 2005 15:05 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/16 "2005-01-31T15:05:19Z")
Ob Javascript reference: In Javascript, the same sort of thing happens. Take a JS-HTML example: myObject.background = 'red'; myObject.style.background\_color = 'red'; Both will 'work' (not throw an error), but not do what you wanted. JS silently creates a new property on the fly, all helpful-like. JS is loosely typed. With ruby, you get a convenient blend of dynamism with strong typing. Not as ridiculously rigid as a strongly-typed language, not as loose as something like JS. > **···** > > > Florian Gross \ wrote: > > > > > Not having your Objects changing types all the time without you > > > noticing. If you forget to initialize a field in PHP it will be > > > converted to zero or an empty String if necessary thus shadowing your > > > bug. Strong typing usually is a requirement for languages where OOP > > > works well. > > > > In Ruby, objects pass for different types all the time. In my own > > recent Ruby code I've mistakenly passed in the wrong types but didn't > > notice because the types responded to the same methods. ---
**Author:** ![Navindra\_Umanee](https://avatars.discourse-cdn.com/v4/letter/n/d78d45/32.png) [@Navindra\_Umanee](https://rubytalk.org/u/Navindra_Umanee)\ **Post date:** [29 January 2005 18:51 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/17 "2005-01-29T18:51:22Z")
Right. So aPig.fly() would work if method\_missing() was defined or if a method Pig.fly() happened to be defined as an alias for Pig.eat\_fly(). In Java, on the other hand, you would clearly get the advantage that you seek here. Cheers, Navin. > **···** > > PA \ wrote: > > > \> This looks more like Java than Ruby... I don't see your point. > > > > Sorry. Forgot to reboot in Ruby mode: > > > > aMethodExceptingToFlyABirdButGivenAPigInstead( aPig ) > > > > And what would happen to this mythical flying pig now? aPig.fly()? > > EXC\_BAD\_ACCESS (aka method\_missing). ---
**Author:** ![David\_A\_Black3](https://avatars.discourse-cdn.com/v4/letter/d/6a8cbe/32.png) [@David\_A\_Black3](https://rubytalk.org/u/David_A_Black3)\ **Post date:** [31 January 2005 02:13 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/18 "2005-01-31T02:13:43Z")
Hi -- > **···** > > On Sun, 30 Jan 2005, PA wrote: > > > On Jan 29, 2005, at 19:27, Navindra Umanee wrote: > > > > > This looks more like Java than Ruby... I don't see your point. > > > > Sorry. Forgot to reboot in Ruby mode: > > > > aMethodExceptingToFlyABirdButGivenAPigInstead( aPig ) > > That's not Ruby mode. That's camel case 🙂 > > David > > -- > David A. Black > dblack@wobblini.net ---
**Author:** ![PA1](https://avatars.discourse-cdn.com/v4/letter/p/71c47a/32.png) [@PA1](https://rubytalk.org/u/PA1)\ **Post date:** [29 January 2005 19:01 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/19 "2005-01-29T19:01:53Z")
Hmm... not sure if I understand that last part... but one thing is very clear though... in Javaland, you simply cannot make pigs fly. In other words, aFlyingPig = (Bird) aPig will not fly. The compiler will just segfault laughing while cursing profanities at you. Cheers > **···** > > On Jan 29, 2005, at 19:51, Navindra Umanee wrote: > > > In Java, on the other hand, you would clearly get the advantage that > > you seek here. > > -- > PA, Onnay Equitursay > [http://alt.textdrive.com/](http://alt.textdrive.com/) ---
**Author:** ![Florian\_Frank2](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@Florian\_Frank2](https://rubytalk.org/u/Florian_Frank2)\ **Post date:** [29 January 2005 19:20 UTC](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086/20 "2005-01-29T19:20:18Z")
PA wrote: > Hmm... not sure if I understand that last part... but one thing is very clear though... in Javaland, you simply cannot make pigs fly. In (non-evil) Ruby it's not possible either, to transform pigs into birds. > In other words, aFlyingPig = (Bird) aPig will not fly. The compiler will just segfault laughing while cursing profanities at you. To have some fun at run-time try this: Bird flyingPig = (Bird) (Object) pig; > **···** > > -- > Florian Frank [Next page](https://rubytalk.org/t/ten-things-every-java-programmer-should-know-about-ruby/16086.md?page=2)