What's the Deal with @JvmDefault?
Kotlin has an annotation called
@JvmDefault which, like most of the “Jvm” prefixed annotations, exists to help massage the Kotlin compiler output to match Java classes in a certain way. This annotation was added in 1.2.40, and has now seen some experimental enhancements in 1.2.50, so it seems worth exploring what this is all about.
Tail Recursion in Kotlin
Tail recursion can be a very elegant way to solve problems that involve a significant number of iterations but are better organized using recursion, without paying the cost you normally pay for recursion. Kotlin can enable the use of tail recursion. To understand the benefits of this, a quick recap would be of value.[Read More]
Kotlin: Reified Type Function Parameters
As most Java programmers know, Java generics are erased at compile-time. This has trade-offs, but the two main reasons for this are:
- Compatibility - Java 1.4 and earlier dealt exclusively in raw types at the VM level. Generics were able to compile without introducing significant new typing to the bytecode and classfile format spec, and having to deal with older classes generated without that typing.
- Simplicity - By erasing to raw types, the JVM doesn’t have to understand specialization; something that has its own complexities and downsides. For example, specialized types are much more challenging to optimize with a just-in-time compiler.
However, knowing the type parameters used at runtime can have real value, and it’s something Java simply doesn’t offer. Kotlin would like to help in this area, but there are many challenges in doing so.[Read More]
Kotlin Logging Without the Fuss
One of Kotlin’s strengths is that generally speaking, the code you might write in Java is generally more compact in Kotlin without losing any of the readability, functionality, or performance.
An odd case where that doesn’t prove to be true is declaring loggers as Java developers.[Read More]
JVMLS 2017: Pattern Matching in Java
This year at JVMLS, Brian Goetz talked about Pattern Matching on the JVM and how it might be modeled. In particular he spoke about:
- How Scala does it
- How C# does it
- How Java might do it
- How Java could do it with amortized constant-time Matching
Kotlin Libraries: Concurrency
Today’s Kotlin library article is about the
kotlin.concurrent package, and everything that adds to the platform.
Java’s concurrency package is already quite sophisticated, and rather than re-invent so many extremely delicate abstractions, the Kotlin authors focused on making the libraries better suited to the language by decorating and shortening various features.[Read More]
Kotlin Libraries: Comparables and Comparators
This is the second article in a series around Kotlin standard library additions. This article is all about the Kotlin comparator factory functions.[Read More]
Kotlin Libraries: I/O operations
This is the first in a series of articles that will quickly go over some of the more interesting bits of the Kotlin standard libraries for Java. Today’s run-through is about some of the more interesting affordances for I/O based programming.[Read More]