Fantom Developer Hiring Guide

Hiring Guide for Fantom Engineers

Ask the right questions to secure the right Fantom talent among an increasingly shrinking pool of talent.

Fantom is a general-purpose, object-oriented programming language that was initially released in 2005 by Brian and Andy Frank. It was designed to be portable across various platforms including Java Virtual Machine (JVM) and JavaScript interpreters. The Fantom ecosystem includes a standard library, a build system, testing framework, and documentation toolset. Its syntax is similar to C#, Java or Kotlin with added features for concurrency management inspired from Erlang's actor model. Despite its versatility and robustness as an efficient cross-platform development tool, it remains relatively obscure within the broader software development community.

First 20 minutes

General Fantom knowledge and experience

The next 20 minutes of the interview should attempt to focus more specifically on the development questions used, and the level of depth and skill the engineer possesses.

How would you handle exceptions in Fantom?

In Fantom, exceptions are handled using 'try-catch' blocks. You can also use the 'throw' statement to throw an exception.

What is the role of the 'using' statement in Fantom?

The 'using' statement in Fantom is used to import a namespace or a type into the current scope. It is similar to the 'import' statement in Java.

How would you create a class in Fantom?

In Fantom, you would create a class using the 'class' keyword followed by the class name. For example, 'class MyClass { }'.

What are the key features of Fantom?

Fantom has several key features including: static and dynamic typing, functional programming, concurrency programming, and a standard library that includes a cross-platform API for file I/O, serialization, reflection, and more.

How would you define Fantom?

Fantom is a general-purpose, object-oriented, portable programming language that runs on the Java Runtime Environment (JRE), JavaScript, and .NET Common Language Runtime (CLR). It is designed to be easy to use, with a familiar syntax for Java and C# developers.

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What youre looking for early-on

Is the candidate able to learn new technologies quickly?

The tech field is always evolving, so it's important for developers to be able to pick up new technologies quickly.

Does the candidate have experience with similar projects or tasks?

Past experience can be a good indicator of how well the candidate will perform in the role.

Can the candidate communicate effectively about technical concepts?

Good communication skills are important for working in a team and explaining technical concepts to non-technical team members.

Is the candidate familiar with the tools commonly used in Fantom development?

Knowing how to use the right tools can greatly increase efficiency and effectiveness in development.

Has the candidate demonstrated problem-solving skills?

This is important because coding and development often involve solving complex problems and finding solutions.

Does the candidate have a solid understanding of Fantom?

This is crucial as the candidate needs to have a good grasp of the language to be able to develop effectively.

Next 20 minutes

Specific Fantom development questions

The next 20 minutes of the interview should attempt to focus more specifically on the development questions used, and the level of depth and skill the engineer possesses.

How would you create a singleton in Fantom?

In Fantom, you can create a singleton using the 'singleton' keyword. For example, 'singleton class MySingleton { }'.

What is the purpose of the 'sys' pod in Fantom?

The 'sys' pod in Fantom provides core functionality and types that are used by all other pods. It includes basic types like Int, Str, Bool, and more.

Describe the difference between static and dynamic typing in Fantom.

In Fantom, static typing means that the type of a variable is known at compile time, while dynamic typing means that the type of a variable is known at runtime. Fantom supports both static and dynamic typing.

How would you implement concurrency in Fantom?

In Fantom, concurrency is implemented using the 'Actor' model. You can create an actor by extending the 'Actor' class and overriding the 'receive' method.

What are mixins in Fantom?

Mixins in Fantom are a type of inheritance that allows you to include behavior from multiple sources in a class. They are similar to interfaces in Java, but they can also include implementation code.

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The ideal back-end app developer

What you’re looking to see on the Fantom engineer at this point.

A skilled Fantom engineer should demonstrate expertise in Fantom language and related technologies, strong problem-solving skills, and experience with systems integration. Red flags include lack of specific examples in their work history or inability to articulate complex technical concepts clearly.

Digging deeper

Code questions

These will help you see the candidate's real-world development capabilities with Fantom.

What does this simple Fantom code do?

class Hello {
  static Void main() {
    echo("Hello, World!")
  }
}

This code defines a class named 'Hello' with a static method 'main'. When this program is run, it will print 'Hello, World!' to the standard output.

What does the following Fantom code do?

class Test {
  Int add(Int a, Int b) {
    return a + b
  }
}

This code defines a class named 'Test' with a method 'add'. This method takes two integer parameters, adds them together, and returns the result.

What will be the output of the following Fantom code?

class Main {
  static Void main() {
    list := [1, 2, 3, 4, 5]
    list.each |Int num| { echo(num * 2) }
  }
}

This code will print the doubled value of each number in the list. So the output will be '2', '4', '6', '8', '10' each on a new line.

What does the following Fantom code do?

class Main {
  static Void main() {
    ActorPool().startup
    Actor { echo("Hello, World!") }.send
  }
}

This code starts an ActorPool and sends a message to a new Actor. The Actor's behavior is to print 'Hello, World!' to the standard output. This demonstrates basic usage of Fantom's concurrency model.

What does the following Fantom code do?

class Person {
  Str name
  Int age
  new make(Str name, Int age) {
    this.name = name
    this.age = age
  }
}

This code defines a class named 'Person' with two fields: 'name' and 'age'. It also defines a constructor 'make' that takes two parameters and assigns them to the fields.

What will be the output of the following Fantom code?

class Main {
  static Void main() {
    echo(Str.locale("en", "US").decimal(1234567.89))
  }
}

This code will print '1,234,567.89' to the standard output. It demonstrates the usage of Fantom's locale-specific formatting.

Wrap-up questions

Final candidate for Fantom role questions

The final few interview questions for a Fantom candidate should typically focus on a combination of technical skills, personal goals, growth potential, team dynamics, and company culture.

How would you optimize performance in a Fantom application?

Performance in a Fantom application can be optimized in several ways, including: using efficient algorithms and data structures, minimizing I/O operations, using concurrency to parallelize tasks, and profiling the application to identify bottlenecks.

What is the role of the 'it' keyword in Fantom?

The 'it' keyword in Fantom is used in closures to refer to the single argument passed to the closure. It is similar to the 'this' keyword in Java, but for closures.

How would you implement polymorphism in Fantom?

In Fantom, polymorphism is implemented through inheritance and interfaces. A class can inherit from another class or implement an interface, and then override the methods defined in the superclass or interface.

Describe the difference between 'const' and 'val' in Fantom.

In Fantom, 'const' is used to declare a constant, whose value cannot be changed once it is assigned. 'val', on the other hand, is used to declare a read-only field, whose value can be assigned once, but cannot be changed afterwards.

What are closures in Fantom and how would you use them?

Closures in Fantom are anonymous functions that can capture variables from their surrounding scope. You can use them as arguments to higher-order functions, or to create function-like objects.

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Fantom application related

Product Perfect's Fantom development capabilities

Beyond hiring for your Fantom engineering team, you may be in the market for additional help. Product Perfect provides seasoned expertise in Fantom projects, and can engage in multiple capacities.