Ruby vs Java Detailed Comparision

Traditionally, we’re going to look at both technologies from a product owner’s perspective, which means learning not only technical differences between the languages but also their actual use across different projects. Here we go.

Warm-up

Before any competition, the contestants need to warm up. It also happens that this term is used by one of the wrestlers, Java, for the lazy class loading of Java Virtual Machine. So, let’s not step out of line and have the competitors spiffed up to the battle.

Ruby

It’s not a secret that our company places a bet on this interpreted scripting language created by Yukihiro Matsumoto in the far 1995. A bunch of deep-rooted technologies like Smalltalk, Python, Perl, Ada, C++, and others had an impact on shaping Ruby’s syntax and features. As a result, we got a technology known for elegant and expressive coding, as well as increased flexibility and productivity of development. It means that engineers take pleasure in writing code with Ruby and are not restricted in their vision on how to execute one thing or another.

At the same time, this technology cannot be called popular. According to the TIOBE index as of December 2018, it is ranked 17th. Nevertheless, the language is not dying and keep afloat with the 3.0 version expected to be released in 2020. To sum up, Ruby allows programmers to enjoy what they do and be productive at once by following the principle of least astonishment.

Ruby key features

Apart from comparing Ruby to Java, let’s take a look at some key things one should know about this gem of a language.

• Open-source
• Interpreted language
• Multi-platform
• Dynamic + duck typing
• Has a smart garbage collector
• Everything including methods, numbers and variable is an object
• You can embed Ruby into HTML
• High scalability
• Applicable for writing CGIs, building web and intranet apps
• Support of different GUI tools including OpenGL, Tcl/Tk, and GTK
• Support of Sybase, Oracle, MySQL, and DB2 connection

Ruby pros and cons

What you will like

- Code length

- Significantly reduced dev time

- Rapid app development

- Flexible and easy-to-understand syntax

- Huge ecosystem of tools & libraries

- Automatic memory management plus

garbage collector

- Big newbie-friendly community

- TDD

- Ruby on Rails

• Supported language for AWS Lambda

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What you won’t like

- Runtime speed is not the Ruby’s best bower

- Inapplicable for projects requiring

memory-intensive tasks

- Those who prefer following strict rules,

won’t like the language’s unopinionated

nature, which allows you to take a variety

of approaches for a particular task

(for example, you have four different

ways to define methods)

Java

Despite Railsware’s unhidden preference towards Matsumoto’s brainchild, Java is also a part of our team’s arsenal. For example, we leveraged it together with other technologies within the Philips Directlife project. That’s to say, we know both of them and are happy to use whichever language best suits the task at hand.

In a sign of numerous Java and Ruby differences to be described a bit later, there is one undisputed similarity – they were born in the same year. Nevertheless, since then, Java has come through 11 versions with Java SE 11 as the latest one (compared to the Ruby’s latest release of 2.6.0). The technologies that influenced the creation of Java include C++, Ada 83, Object Pascal and others.

The TIOBE index shows that this compiled programming language overcame C in ranking and holds the first position as of the end of 2018. Moreover, it is a primary technology for Android native app development, which by the way was recently enhanced with Kotlin. Another facet of Java is that it is also an ecosystem of tools including Java Development Kit (JDK) for writing/running/compiling Java code, Java Virtual Machine (JVM) for running software built with Java and JVM languages within the same infrastructure to some degree of interoperability (for example, Kotlin for expressiveness and conciseness, Scala for functional programming, etc.), and Java Runtime Environment (JRE) for running Java apps. The basic points why developers opt for this technology are its reliability, platform independence, and ease of use. Let's see Project with Ruby On Rails

Java key features

• Open-source
• Object-oriented language (there are objects, as well as primitives, which are limited to a few types)
• Both compiled and interpreted language
• Architecture neutrality
• Static typing
• Built-in security
• Dynamic compilation and dynamic loading of classes
• Automatic garbage collection
• Simple memory management model
• Multithreading capabilities
• Platform independence

Java pros and cons

What you will like

- Static typing to build large codebase

- Syntax derived from C

- Code design thinking

- Standard for enterprise computing

(for example, bank related software is

mostly written in Java)

- Huge ecosystem

- Built-in security manager

- TDD

- Backward compatibility

- Write Once Run Anywhere concept, which

means you can run your program be it

built in Java or another programming

language on any JVM-equipped device

regardless of the operating system

- Remote Method Invocation (RMI) - a

methodology for distributed computing

- Automatic memory management plus garbage

collector

- Multithreading capability

- Java is a basic study for many colleges

meaning there is no shortage in talent

- Huge amount of educational resources, as

well as tools

- Plethora of job offers to Java specialists

- Huge ecosystem with the support of multiple

languages that compile to bytecode for JVM

(as a result, you get more tailored languages

for specific tasks like building a web app based

on microservices architecture where each

microservice can be created using a different

language and then run together using an app

container like Apache Tomcat)

What you won’t like

- Performance may suffer due to compilation,

as well as versatile CPU-intense features

like garbage collector

- JVM has a significant overhead on memory

- Verbosity makes the code explicit and more

difficult to read and scan

- Garbage collector might cause noticeable delays

in code execution

- Memory leaks

- NullPointerException (aka the billion dollar mistake)

- Long compilation time

Java vs. Ruby similarities and differences from a tech viewpoint

Before the face-off where you can learn more about Java vs. Ruby’s speed, productivity, performance, complexity and other aspects, let’s take a look at fundamental differences and similarities between them.

What do they differ in?

Interpreted or compiled

As you know, for interpreted languages there is no need to compile the code into machine-language instructions before executing most of its implementation. For compiled technologies, we need compilers to generate machine code from the source one. Everything is clear with Ruby – it’s an interpreted language. As for Java, you can find a lot of sources claiming that it’s strictly compiled. At the same time, along with JIT (just-in-time) compilation of the bytecode from the Java compiler, some JVM implementations may interpret the bytecode as well. It is not an interpreter that you can observe in other programming languages like Ruby, but it’s also possible to interpret the Java code directly. So, Java can be called both an interpreted and compiled technology.

Dynamic or static typing

A polar opposite difference between Java and Ruby lies in the way they apply a “type” to a variable. Static typing means that a programmer has to define what type each variable is before using them – types are checked before run-time. At the same time, in some JVM languages, types can be derived upon initialisation from other code. For example:

int number = 1 vs. number = 1
It’s super easy for the compiler to derive the type. Another example would be:

int methodReturningInteger() {

return 42;

}

number = methodReturningInteger();

compiler can figure out whether it is int.

Such hybrid of static and dynamic typing can be found at many JVM languages including Kotlin and Apache Groovy, but not at Java, which is a genuinely statically typed technology.

In dynamically typed languages, a programmer does not have to define types every time. Ruby doesn’t rely on types at all and cares about methods it needs to call on a given object (the famous duck-typing).

1. class Animal
2. attr_accessor :name
3. end
4. class Desk
5. attr_accessor :name
6. end

and later…

1. animal = Animal.new
2. desk = Desk.new
3. stuff = [animal, desk, animal, desk]

It’s absolutely fine in Ruby. In statically typed languages the both classes would have to have a common interface (another type) or common base class they can both inherit from. What’s more:

1. whatever = stuff.first
2. print whatever.name

is also fine as long as the object responds to the method called name.

Statically typed languages show better performance at run-time because they check types before running. At the same time, dynamic typing is associated with better project bootstrapping and changes smoothing, which is especially important in the early to middle stages.

Pure object-oriented or hybrid object-oriented

Object-oriented programming (OOP) allows engineers to define the type of data and its structure, as well as specify the set of functions applied to it. In the class-based OOP paradigm, an object is a chunk of memory containing different data (variables, functions, etc.). We know that Ruby defines everything as an object including all predefined and user-defined types. It is a pure object-oriented language. Java does not fall under this category because of the eight primitive types (byte, short, int, long, float, double, char, and boolean) that are not classified as objects. Hence, it is not a pure OOP technology and is usually referred to as a hybrid one. You can also see Ruby Vs Python

Method overloading

This term is an important OOP feature and denotes having methods with the same name but taking a different set of arguments. For Java, method overloading is a form of implementing generics. Since variables in Ruby are not typed, the arguments cannot differ in type, and this feature is not associated with this language.

Operator overloading

As for operator overloading, Ruby supports the feature that allows developers to define an operator (+ or *) for user-defined types, while Java does not.

What are the similarities?

Beside the difference between Ruby and Java, they share some similar features as follows:

Garbage collection

It is a great technique, which allows engineers to build a memory safe system without the responsibility of memory management. Garbage collection is inherent in many high-level languages including Ruby and Java. At the same time, these technologies have a little variation as for the collectors they leverage. In addition to the mark-sweep algorithm associated with Ruby, JVM has such types of collectors as generational, incremental, and mark-compact as well.

Multithreading

Both languages use standard libraries for concurrent and parallel execution of tasks. In Java, it can be achieved to run code in parallel – utilising all the CPU cores. In Ruby, it cannot be achieved and all you have is mere concurrency, which means that one thread starts, then it’s paused, another one is resumed, then it goes back to the first one, etc.

Built-in security

In terms of Ruby vs. Java security, the web is full of claims that both are secure languages. Well, a disclaimer is needed here. Any language itself cannot be secure or protect a software created with it from vulnerabilities. At the same time, the technologies we’re comparing do have special features that facilitate avoiding common security flaws. As for Java, it is free of pointers, which can sometimes allow unauthorized access to memory, and has a Security Manager that allows you to run apps in a sort of sandbox to detect possible defects. Rubyists can enjoy a plethora of security libraries (they call them gems) including Brakeman, bundler-audit, Codesake:: Dawn, Tarantula, and others.

Ecosystem

“It has an extremely large ecosystem of libraries and tools” – this statement is applicable for both Java and Ruby. Meanwhile, each technology has its own peculiarities to be understood for the project you’re going to work on. The most important element of the Java ecosystem is JVM, which sets the background for languages other than Java, e.g., Kotlin, to flourish. Rubyists do not have a virtual machine in possession and take advantage of gems – libraries containing a specific piece of functionality like handling money, credit card integration, and versatile auxiliary tools to facilitate coding. JARs are a kind of analog of Ruby gems in Java. However, they have some qualities that make them very different from gems. JAR files are the deployment format for Java containing classes, icons, property files, and other resources. It would be cool to compare Ruby gems vs. Java JARs in detail someday.

Performance

We’ve mentioned that poor performance is a drawback inherent to both technologies. This value can be defined only if compared with a better or worse value. When checking the Ruby vs. Java performance, the former technology is leading. Ruby is simpler hence faster than Java. The code written in Ruby changes on the fly, while its competitor needs to generate the byte code before it can run. The Ruby performance supremacy is true for small tasks only, while Java recoups huge computational needs. It performs better when the same tasks are performed repeatedly. I guess, the draw as for performance will be fair enough here.

Productivity

Did you read about Ruby as a productivity booster, which allows you to cut your pipeline by one-third? Some authors claim even 10x faster development time. However, none of them managed to give some proof or at least specify the technology they compared Ruby with. All these terrific figures appeared for a reason – this programming language is a perfect fit for rapid development. A task, which will force you to write a bunch of C-syntax code lines in Java, takes fewer lines in Ruby. Moreover, the latter offers a high level of flexibility and readability. In practice, you spend less time on bug fixing and accelerate your pipeline. As for the Java vs. Ruby code comparison, the latter is an undisputed winner.

Talent demand

Being the most popular language on the planet, Java is definitely a leader in the market of talents. Many experts predict it to be one of the most in-demand technologies in the coming years along with Python and JavaScript. And where is Ruby? It’s not even in the top ten, unfortunately. Nevertheless, it does not mean that the Ruby vs. Java job market comparison is pointless. The evident lower popularity of Ruby causes a lack of talent proficient in this language. For that reason, the average Rubyist’s salary in the US is over $137K per year, while Java experts earn a bit more than $120K. Long live Ruby on Rails!

Which technology to choose for a project?

Let’s suppose, you have not made up your mind on which technology to choose for your project and are still at the crossroads. On the one hand, you have Ruby with its undisputed efficiency in development and elegance in work. On the other hand is Java, which virtually reigns the world of programming and can be used literally for any task you need. We’ll try to help you in decision-making by comparing Ruby vs. Java productivity.

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When to use Ruby

When it comes to web app development, Ruby with its powerful framework should be the first option to consider. Here you can discover why use Ruby on Rails. At the same time, RoR is not a silver bullet, which is fit for all tasks. However, it is best for startups with the following requirements:

• Your idea is driven purely by the value to be provided to customers
• No fixed product concept is available yet
• Concise timeframe
• Frequent functionality revisions/project changes are expected
• Fast prototyping
• Any industry or business sector
• Small to middle app size

When to use Java

It goes without saying that Ruby isn’t Java, but it’s not a down-the-line argument to opt for the “King of programming”. This language is associated with being an enterprise-grade technology aimed at big data products and apps demanding high traffic and user base. Web app development is not Java’s focus area. Despite its huge popularity, a relatively small percentage of web apps are built with the technology. Java will fit if your startup is associated with the following:

• Memory-hungry and complex app architecture
• High-volume and high-security product
• Interaction with a number of adjacent systems like mainframe back-ends, databases, peer web-services, background batch-processing systems, etc.
• Unlimited timeframes and resources
• You’re running or going to run your own server (otherwise, be prepared to drain your purse for hosting services)

The reality is that Java is less in demand on the web app market than Ruby. Some of the reasons that scare off startups include the language’s verbosity and static typing, which slow down the development process. At the same time, Java is a reliable and powerful technology and is a go if you want to create something solid, complex, easily scalable, and completely error-free.