When comparing Java vs Ceylon, the Slant community recommends Java for most people. In the question“What is the best programming language to learn first?” Java is ranked 22nd while Ceylon is ranked 31st. The most important reason people chose Java is:
Because Java is statically typed, integrated development environments (IDEs) for Java can provide a lot more feedback on errors you will encounter. Java IDEs can give you specific errors in the location where they occur without having to run the code every time. This makes is faster to debug and learn from your mistakes. IDEs also have extensive auto complete capabilities that can help you learn the programming libraries you are using faster and tell you what functions are available.
Ranked in these QuestionsQuestion Ranking
Pro Fantastic IDEs
Because Java is statically typed, integrated development environments (IDEs) for Java can provide a lot more feedback on errors you will encounter. Java IDEs can give you specific errors in the location where they occur without having to run the code every time. This makes is faster to debug and learn from your mistakes.
IDEs also have extensive auto complete capabilities that can help you learn the programming libraries you are using faster and tell you what functions are available.
Pro Most commonly used language in industry
Pro Consistent programming standards
Most Java code follows very standardized coding styles. This means that when you're starting out, there are fewer questions about how you should implement something as the programming styles and patterns are well established and consistent. This consistent style means that it's often easier to follow others' example code, and that it's more likely to meet at least a certain minimum standard of quality. This discipline with consistent stylistic standards also becomes useful later, when collaborating on projects with larger teams.
Pro Best introduction to "C style" languages
The Java syntax is very similar to other C style languages. Learning the fundamentals of Java will port over well to other languages so you can apply what you've leaned to other languages afterwards.
Pro Introduces you to object oriented languages
Object Oriented Programming (OOP) is a paradigm that teaches you to split your problem into simpler modules with few connections between them; it's the most common paradigm used in industry. Java is the best choice as an introduction to object oriented languages because, as a statically-typed OOP-only language, it very clearly highlights core OOP principles such as encapsulation, access control, data abstraction, and inheritance.
While a scripting language provides more flexibility and terseness, learning a scripting language first would not instill these fundamental concepts as well, as they tend to obscure details such as how types work, and are less encouraging of an object oriented style.
Pro Platform Independent
Because of the Java Virtual Machine, the Java programming language is supported wherever a JVM is installed.
Pro Massive amount of libraries and APIs
Java has been around for such a long time that there have been tens of thousands of APIs and libraries written for almost anything you want to do.
Pro Strong static typing, null safe and flexible, almost dynamic type system
The compiler prevents you from using a potentially null variable, unless you check it is not null. Ie. it forces you to check a potentially null value before using it.
The type system is strict, but flexible, allowing union and intersection of types, covariant and contravariant types, reified types, etc.
Type inference and union types allows a dynamic programming style, close of JS spirit.
It brings type safety to JS, allowing to define interfaces to existing JS APIs, yet using the
dynamic keyword for flexible calls in the JS ecosystem.
Pro Excellent IDE support
Ceylon has reified generics, so it doesn't loose the type of collections at runtime. This makes autocompletion, debugging, etc. first-class. The Eclipse plugin makes it a full-fledged Ceylon IDE, and an IntelliJ IDEA plugin is in the works.
Pro Great tutorial
Gavin King, main author of the language, has a great, clear technical writing style, making understandable difficult concepts like variance or sound type system.
Pro Try it out in the browser
It has a Web IDE: http://try.ceylon-lang.org/ with impressive demos: http://try.ceylon-lang.org/?gist=bd41b47f325b6d32514a so you can try it without installing anything, and see the JS generation / interop in action.
Pro Excellent documentation
The language specification is very complete and up to date; also, the language module is very well documented.
Pro Easy to learn even if you don't have prior programming experience
Ceylon is indeed fairly easy and readable. Of course those ones who know OOP and a bit of functional programming concepts will feel almost at home right from the start.
Pro Generate HTML
HTML generation is supported right in the SDK.
Pro Same code in backend and frontend
Con Worst-of-both-worlds static type system
It's just barely good enough to make decent IDEs, but it's not at the level of Idris or even Haskell. For large enterprise projects, the IDE support is important, but the static typing in Java just gets in the way for the smaller projects beginners would start with.
Python is duck typed and this makes small programs easy to develop quickly, but the price is that you have to write unit tests to avoid breaking larger programs. In contrast, you can be reasonably certain that a program that actually compiles in Idris does what you want, because assertions are built into the powerful type system. Java can't make that claim and still requires unit tests. Java has the worst of both worlds because of its poor static type system.
Con Lacks modern features
Java evolves very slowly - lambda expressions weren't available until Java 8 (which is not available on Android), and despite getters/setters being a long-time convention, the language still doesn't have native accessor syntax (a la C#'s properties). It's unlikely newer, popular features like list comprehensions or disjoint union types will be available anytime soon. While not strictly required for novice programmers, these make problems more complicated and tedious than they need to be - for example, when a simple local function would do, (portable) Java demands anonymous inner classes, an interface and a class, or worse, no abstraction at all.
Con Confusing mis-features
Some features in Java can be quite confusing for beginners.
Encapsulation is needlessly obfuscated with a confusing access control model. As an example, the "protected" keyword not only grants access to child classes, but to the entire package. Since small programs are written as one package, it becomes functionally equivalent to "public".
In OOP, everything is supposed to be an object, but, in Java, primitive types such as integers, booleans and characters are not, and must be handled as special cases.
Java continues to lack many high-level features, and, particularly prior to Java 7, compensated by adding confusing Java-only features, such as anonymous subclasses. Some example code is unreadable without knowing a special-case feature, libraries differ in style based on when they were released or what platform they target(e.g., Android vs. Desktop), and some solutions just aren't available on some platforms.
Con Too verbose
- A Hello world needs package, class, static method and the actual
- Reading a line from input requires instatiating 5 objects in the right order.
- Exceptions are everywhere, particularly since all values are nullable.
- Java has a getter/setter culture, but without native syntax support.
- portable Java code lacks anonymous functions, and continues to lack good support for partial application, compensating instead with verbose design patterns, kludges like anonymous inner classes, or just inline code.
- It is statically typed without type inference, with a culture that promotes long class names.
- Poor support for sum-types and pattern matching leads to overuse of inheritance for dynamic dispatch and chains of nested conditionals
Especially for beginners, this can make reading Java code feel overwhelming; most Java courses tell students to simply copy, paste, and ignore a significant percentage of the code until they've learned enough to understand what it means.
For experienced programmers, this makes Java feel tedious, especially without an IDE, and actively discourages some solutions and some forms of abstraction.
Con Locks you into the static OOP mindset
Con Half-baked generics
Type erasure means it doesn't even exist at runtime. The whole generics system is confusing for beginners.
Con Garbage collection may teach bad habits
Java is a garbage collected language and it does not force programmers to think about memory allocation and management for their programs. This is fine most of the time. However, it may cause some difficulties in adjusting to a non-GC language (such as C for example), where memory management needs to be done manually. But if good coding practices and habits are followed, this shouldn't be much of a problem.
Con Enforces some misguided principles
Java utilizes principles that organize code into "classes" as the central concept, instead of more familiar organizational methods.
Con Long learning curve
Con Static typing but no type inference
The type system gets in your way more than it helps. Heavy IDE support is absolutely required for reasonable productivity. This means beginners have to learn not just the language, but eventually a complex, heavyweight IDE too.
Con Checked exceptions
Catch blocks can be a frequent source of mistakes.
Con Currently has large runtime
Ceylon 1.2 needs a language runtime of 1.55 MiB, and the Collection library adds another 370 KiB. That's a lot for the Web...
Now, this has to be put in perspective: if you use Ceylon to make a web application, these files will be loaded once, then cached by the browser (that's not casual browsing).
Moreover, most servers compress such resource, and the numbers become respectively 234 KiB and 54 KiB, which is more reasonable...
Con Lack of physical or electronic books
We should hope Red Hat or anyone interested would take the time and write one. That would strengthen the maturity of the language, but Ceylon is rapidly developing which can make the author's efforts futile because his or hers work will become obsolete soon.
The second hindrance is, of course, popularity of the language which can't give much to the pockets of the author (however, Dart's unpopularity at start didn't prevent it to have a lot of printed material, but that's Google's child, we know).