teachingkotlin

When you start migrating your Java code to Kotlin, you will encounter multiple subtle changes that might catch you off guard. I’ll document some of these gotchas that I and other people I follow have found and written about. Splitting strings Java’s java.lang.String#split method takes a String as it’s first argument and creates a Regex out of it before attempting to split. Kotlin, however, has two variants of this method. One takes a String and uses it as a plaintext delimiter, and the other takes a Regex behaving like the Java method we mentioned earlier....

Even the variables in Kotlin are supercharged! Let’s start with a simple data class and see how the variables in there behave. data class Student(val name: String, val age: Int, val subjects: ArrayList<String>) To use the variables in this class, Kotlin let’s you directly use the dot notation for accessing. >>> val s1 = Student("Keith Hernandez", 21, arrayListOf("Mathematics", "Social Studies")) >>> println(s1.name) Keith Hernandez >>> println(s1) // data classes automatically generate `toString` and `hashCode` Student(name=Keith Hernandez, age=21, subjects=[Mathematics, Social Studies]) For Java callers, Kotlin also generates getters and setter methods....

Classes in Kotlin closely mimic their Java counterparts in implementation, with some crucial changes that I will attempt to outline here. Let’s declare two identical classes in Kotlin and Java as a starting point. We’ll be making changes to them alongside to show how different patterns are implemented in the two languages. Java: class Person { private final String name; public Person(String name) { this.name = name; } } Kotlin:...

Anybody familiar with my work knows that I am a fan of the Kotlin programming language, especially it’s interoperability with Java with respect to Android. I’ll admit, I’ve not been a fan since day one. The abundant lambdas worried me and everything being that much shorter to implement was confusing to a person whose first real programming task was in the Java programming language. As I leaped over the initial hurdle of hesitation and really got into Kotlin, I was mindblown....