Java SE 8

Java SE 8

The newest release of Java is Java SE 8, with the developer’s kit being called JDK 8. It has an internal version number of 1.8. JDK 8 represents a very significant upgrade to the Java language because of the inclusion of a far-reaching new language feature: the lambda expression. The impact of lambda expressions will be profound, changing both the way that programming solutions are conceptualized and how Java code is written. As explained in detail in Chapter 15, lambda expressions add functional programming features to Java. In the process, lambda expressions can simplify and reduce the amount of source code needed to create certain constructs, such as some types of anonymous classes. The addition of lambda expressions also causes a new operator (the –>) and a new syntax element to be added to the language. Lambda expressions help ensure that Java will remain the vibrant, nimble language that users have come to expect.

The inclusion of lambda expressions has also had a wide-ranging effect on the Java libraries, with new features being added to take advantage of them. One of the most important is the new stream API, which is packaged in java.util.stream. The stream API supports pipeline operations on data and is optimized for lambda expressions. Another very important new package is java.util.function. It defines a number of functional interfaces, which provide additional support for lambda expressions. Other new lambda-related features are found throughout the API library.

Another lambda-inspired feature affects interface. Beginning with JDK 8, it is now possible to define a default implementation for a method specified by an interface. If no implementation for a default method is created, then the default defined by the interface is used. This feature enables interfaces to be gracefully evolved over time because a new method can be added to an interface without breaking existing code. It can also streamline the implementation of an interface when the defaults are appropriate. Other new features in JDK 8 include a new time and date API, type annotations, and the ability to use parallel processing when sorting an array, among others. JDK 8 also bundles support for JavaFX 8, the latest version of Java’s new GUI application framework. JavaFX is expected to soon play an important part in nearly all Java applications, ultimately replacing Swing for most GUI-based projects. Part IV of this book provides an introduction to it.

In the final analysis, Java SE 8 is a major release that profoundly expands the capabilities of the language and changes the way that Java code is written. Its effects will be felt throughout the Java universe and for years to come. It truly is that important of a upgrade.

The material in this book has been updated to reflect Java SE 8, with many new features, updates, and additions indicated throughout.