Ninja Squad books and online courses about Angular and Vue

Pay what you want for "Become a Ninja with Angular" and "Become a Ninja with Vue", our DRM-free ebooks and online courses about these popular frameworks. Their "Pro Pack versions", our online courses, will save you hours on your projects by building a complete and tested application, step by step.

Kotlin: from Zero to Ninja

Kotlin is now the most used language on the JVM after Java. It's also very much loved, and for good reasons: pragmatic, simple, less verbose than Java, but not too concise either, completely compatible with Java, well integrated in popular frameworks like Spring Boot and others. It's also the official language of the Android platform. In this training, you will learn the essentials of the language, by practicing on small exercises, with the help of your teacher or course, but also of automated tests.

kotlin logo

2 days - 1,250

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Slashed price for Heroes!

All of our trainings are subject to the slashed price for Heroes.
Ask for a -30% price cut if you are: volunteering on tech community events, committer on open source projects, freelance without training program from an employer, or unemployed.

More on our blog (in French).

All our trainings are available and customisable to suit your entreprise's needs. Contact us to have a special price and program.
We live around Lyon, France, but we may travel to give them.
Ninja Squad is a training agency registered under French number 82 42 02523 42.


  • Master the syntax of the language.
  • Understand and use the design principles of the language.
  • Interoperate with Java code.
  • Be familiar with the essentials of the Kotlin standard library.


This training is for developers who want to discover the Kotlin language, but already are familiar with Java.


Knowledge of the basics of Java, OO and functional programming. A doubt on your current knowledge level? Send us an email!


The training can be followed in person or remotely, during public sessions that we organize regularly, or during a session dedicated to your team. You can register for a session up until the starting date, in the limit of available seats (usually 6 or 7). We may have to re-schedule a session if we don't have at least 3 persons registered, up until 2 weeks before the starting date. Do not hesitate to contact us to define your needs, and check if the training is the right one for you.


The automated tests allow checking if your code is correct. The trainer will of course answer the questions and have a look at the written code to spot things that can be improved.


Each trainee must have his/her own computer to be able to do the exercises (the OS can be whatever you prefer), and an Internet connection. For an in-house training, the trainer will also need a video-projector, an Internet connection, and a whiteboard or paperboard.


Day 1

Getting started
  • Overview of the language
  • Differences and similarities with Java
Variables and types
  • Variables
  • Primitive and reference types
  • Nullable and non-nullable types
  • Platform types
Expressions and statements
  • Control flow
  • Safe call and Elvis operators
  • Literals for primitive types
  • Strings, interpolation and raw strings
  • Differences with Java
  • Visibility
  • Inheritance
  • Mutable and immutable properties
  • Lazy initialization
  • Constructors
  • Nested and inner classes
  • Sealed classes
  • Objects and companion objects
  • Interfaces
  • Data classes
  • Inline value classes

Day 2

  • Named parameters
  • Exceptions
  • Varargs
  • Lambdas and function references
Extension functions (and somewhat related topics)
  • Scope functions
  • Inline functions
  • Extension properties
  • Operator overloading
  • Infix functions
  • Domain Specific Languages
  • Destructuring
  • Generic bounds
  • Invariance, use-site and declaration-site variances
  • Reified type parameters
  • Mutable and read-only collections
  • Factory functions
  • Functions and operators


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Jean-Baptiste Nizet will be the trainer for this session. He has been using Kotlin, along with Java and TypeScript, for several years, in personal and customer projects. He has over 20 years of experience in development. Our trainers are passionate and experts in their fields. With dozens of trainings each year, and that for the past 10 years, our trainers have become masters in the art to teach a technology to a team.


This training costs 1250€HT per trainee for a public session. These sessions should happen every 2 or 3 months if enough people are interested. We can also plan a dedicated session for your team if you need to: send us an email in that case for a personalized quote.

Remote teaching

For a remote training, the trainer will be in a virtual face-to-face 100% of the time to teach a new concept or help the trainees during the exercises. We use Google Meet to have a private classroom. To follow the progress of the trainees while they do the exercises, we use the "Code With Me" plugin of IntelliJ IDEA.


People with disabilities should contact us directly so we can figure out the best conditions for them.

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About us

Ninja Squad is a training agency registered under French number 82 42 02523 42.

We are also certified by Qualiopi for the quality of our trainings.

See our certificate.