Scala is a general purpose programming language designed to express common programming patterns in a concise, elegant, and type-safe way. It smoothly integrates features of object-oriented and functional languages, enabling Java and other programmers to be more productive. Code sizes are typically reduced by a factor of two to three when compared to an equivalent Java application.

Many existing companies who depend on Java for business critical applications are turning to Scala to boost their development productivity, applications scalability and overall reliability.

For example, at Twitter, the social networking service, Robey Pointer moved their core message queue from Ruby to Scala. This change was driven by the company's need to reliably scale their operation to meet fast growing Tweet rates, already reaching 5000 per minute during the Obama Inauguration. Robeys thinking behind the Twitter Kestrel project is explained in the developers live journal. His concise 1500 lines of Scala code can be seen as he has generously made them available as an open source project.

Many top-notch programmers and industry leaders have already been captivated by Scala. They have become quite vocal encouraging others, creating a growing range of books on Scala and an almost endless supply of tips for Java programmers new to Scala, some of which are collected in "Java to Scala with the help of experts". While here on the scala-lang site, there is a broad range of material too, from introductory Scala tutorials to advanced language research topics, or look at some Scala code examples, or just get started by installing Scala now.

Existing Java code and programmer skills are fully re-usable. Scala programs run on the Java VM, are byte code compatible with Java so you can make full use of existing Java libraries or existing application code. You can call Scala from Java and you can call Java from Scala, the integration is seamless. Moreover, you will be at home with familiar development tools, Eclipse, NetBeans or Intellij for example, all of which support Scala. It does not take long to become an effective Scala programmer when you are half way there already!

The Scala compiler is mature and proven highly reliable by years of use in production environments, The compiler was written by Martin Odersky who also wrote the Java reference compiler and co-authored the generics, used by millions of Java programmers today. You can be confident his implementation of the Scala compiler produces byte code that performs every bit as good as comparable Java code.

After having written hundreds of thousands lines of Java himself, Martin Odersky, Professor at EPFL, was well aware of the frustrations faced by Java programmers. He formed the vision of applying the best knowledge of the academic research community to the problem of making the Java programming experience better, even fun. His first pragmatic step was Java Generics, seen as a major success by the Java community. But for the full vision of scalable concurrent programming to be achieved he saw that the basic Java syntax would need to change. You simply couldn't get there from here. But a deceptively simple shift in syntax gained better uniformity to the object-oriented aspects of Java, and this in turn enabled a natural fusion with functional programming concepts which are critical for tackling concurrency. In 2001 Scala was born.