Hiring guide for Xtend Engineers

Xtend Developer Hiring Guide

Xtend is a statically-typed programming language that runs on the Java Virtual Machine (JVM). It is a flexible and expressive dialect of Java, which compiles into readable Java 5 compatible source code. Xtend is equipped with powerful features such as type inference, extension methods, lambda expressions, operator overloading, and template expressions. It also allows for functional-style programming through its support for higher-order functions and immutability. Xtend retains the syntax of Java in many ways but enhances it with additional functionality to make coding more efficient and enjoyable.

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

First 20 minutes

General Xtend app knowledge and experience

The first 20 minutes of the interview should seek to understand the candidate's general background in Xtend application development, including their experience with various programming languages, databases, and their approach to designing scalable and maintainable systems.

How would you compile an Xtend program?
You can compile an Xtend program using the Xtend compiler which is integrated in the Xtend IDE. You just need to save the file and the IDE automatically compiles it.
What are the main features of Xtend?
Xtend has several features such as extension methods, lambda expressions, type inference, operator overloading, and template expressions.
Describe the difference between Xtend and Java.
Xtend is a statically-typed programming language which is fully interoperable with Java but has a more expressive syntax. It provides functional programming features and allows for more concise code.
How would you use lambda expressions in Xtend?
In Xtend, you can use lambda expressions to create anonymous functions. For example, '[int i | i * i]' is a lambda expression that represents a function that squares an integer.
What are extension methods in Xtend and how would you use them?
Extension methods in Xtend are static methods that can be called as if they were instance methods of their first parameter's type. You can use them to extend the functionality of existing classes.
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What you’re looking for early on

Does the candidate have a solid understanding of Xtend language?
Has the candidate demonstrated problem-solving skills?
Is the candidate able to communicate effectively?
Does the candidate have experience with other programming languages?

Next 20 minutes

Specific Xtend development questions

The next 20 minutes of the interview should focus on the candidate's expertise with specific backend frameworks, their understanding of RESTful APIs, and their experience in handling data storage and retrieval efficiently.

How would you implement operator overloading in Xtend?
In Xtend, you can implement operator overloading by defining methods with special names like 'plus' for '+', 'minus' for '-', etc. The methods should be marked with the 'operator' keyword.
Describe the difference between 'val' and 'var' in Xtend.
'val' is used to declare a read-only (final) variable, while 'var' is used to declare a mutable variable in Xtend.
What are the benefits of using Xtend's type inference?
Type inference in Xtend allows you to omit type declarations in many cases, making the code more concise and readable. The compiler infers the type from the context.
How would you use template expressions in Xtend?
Template expressions in Xtend are multi-line string literals that can contain expressions enclosed in '${}'. They are useful for generating code, SQL queries, etc.
What are the advantages of using Xtend over Java?
Xtend offers several advantages over Java such as a more expressive syntax, functional programming features, operator overloading, and the ability to write more concise code.
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The ideal back-end app developer

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

At this point, a skilled Xtend engineer should demonstrate strong problem-solving abilities, proficiency in Xtend programming language, and knowledge of software development methodologies. Red flags include lack of hands-on experience, inability to articulate complex concepts, or unfamiliarity with standard coding practices.

Digging deeper

Code questions

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

What does the following Xtend code do?
def helloWorld() {
  println('Hello, World!')
This code defines a function named 'helloWorld' that prints 'Hello, World!' to the console.
What does the following Xtend code do?
val list = #[1, 2, 3, 4, 5]
val doubled = list.map[i | i * 2]
This code creates a list of integers and then creates a new list 'doubled' where each element is the double of the corresponding element in the original list.
What will be the output of the following Xtend code?
val list = #[1, 2, 3, 4, 5]
val filtered = list.filter[i | i % 2 == 0]
This code will print out all the even numbers from the list, which are 2 and 4.
What does the following Xtend code do?
class MyThread extends Thread {
  override run() {
    println('Thread is running')
val t = new MyThread()
This code defines a new class 'MyThread' that extends the 'Thread' class. It overrides the 'run' method to print 'Thread is running' when the thread is started. Then it creates an instance of 'MyThread' and starts the thread.

Wrap-up questions

Final candidate for Xtend Developer role questions

The final few questions should evaluate the candidate's teamwork, communication, and problem-solving skills. Additionally, assess their knowledge of microservices architecture, serverless computing, and how they handle Xtend application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

How would you handle exceptions in Xtend?
Exception handling in Xtend is similar to Java. You can use try-catch-finally blocks to handle exceptions.
Describe the difference between a 'def' and a 'function' in Xtend.
In Xtend, 'def' is used to define a method, while 'function' is not a keyword and is not used to define methods.
How would you create and use a custom annotation in Xtend?
You can create a custom annotation in Xtend by defining an interface with the '@interface' keyword. You can then use it by prefixing it with '@' and placing it above the element to be annotated.

Xtend application related

Product Perfect's Xtend development capabilities

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