When defining a variable of a generic type we can use a wild card instead of specifying the exact secondary type the generic type uses.
object HelloSample
{
def main(args:Array[String]):Unit =
{
val a:MyStack[SportCar] = new MyStack[SportCar];
val b:MyStack[_ <: Car] = a;
}
}
class Car
class SportCar extends Car
class MyStack[T]
The following video clip shows the execution of this code sample and explains it.
Practical advice for speakers who want to deliver a memorable talk.
Avoid these frequent CFP pitfalls and boost your chances of being selected.
Turn your speaking dream into reality—practical tips for writing a winning CFP proposal.
Explore Stable Values – a new Java 25 upcoming feature (JEP 502) enabling lazy initialization with immutable performance and JVM-level optimizations.
MongoDB 2025 Tel-Aviv took place in Hilton Tel-Aviv. It was a great learning experience.
PyCon IL 2025 took place on September 9, 2025. It was a marvelous celebration for Python developers in the Israeli community.
If you consider running a startup the bootstrap way then you might get some insight from the lessons I learned.
Learn about the considerations we should take into account when choosing whether to move forward from Java to Kotlin or to Scala.
Accessibility | Career | Conferences | Design Patterns | JavaScript | Meetups | PHP | Podcasts | Python | Self Learning
Teaching Methodologies | Fullstack | C++ | C# | CSS | Node.js | Angular | Java | Go | Android | Kotlin | Swift | Academy
Front End Development | Scala | Architectures | Cloud | Big Data | Internet of Things | Kids Learn Programming
Coding is Art! Developing Code That Works is Simple. Develop Code with Style is a Challenge!