New features of Java 8 and "Core Java Technology for Busy People"

First of all, this book "Java Core Technology for Busy People" is a thin version of "Java Core Technology". Its content is full of essence, and the book is very effective for programmers who need to quickly understand java. The following two points to talk about java 8 and the content of this book.

The new features of Java 8 and the improvement of the original functions:
First: the improvement of the interface, now it is completely possible to define static methods in the interface, and the interface does not provide a default implementation of any method of the Object class. Java 8 introduced functional interfaces. An interface is a functional interface if it defines only one abstract method. A very valuable property of functional interfaces is that they can be instantiated using lambdas.
Second: Improvements to the function and stream packages. As an early proof of Comparator and Runnable, the interfaces already defined in the JDK happen to be functional interfaces compatible with lambda expressions. The same way you can define any functional interface or third-party library in your own code. But there is a specific form of functional interface, and it is broad and general, which did not exist in the previous JDK. The java.util.stream package provides facilities to "support functional-style value manipulation on streams".
Third: generic interface improvements. This is an effort to improve the compiler's ability to determine generics that could not be done before. In previous versions of Java there were many situations where the compiler could not calculate the generic type for a method.
There are many other improvements, such as collection API accessories, adding concurrent API, java.time, java.lang, java.sql and a series of content updates.

My opinion on the sample chapters of this book:
At the beginning of the book, there is a preface recommended by some big cows, followed by the author's foreword. I usually read the author's foreword carefully when I read the book. The author's sentence impressed me deeply "This book is written for application software programmers", indicating that the style of this book is very high. This book does exactly that.
The second chapter in the sample chapter introduces object-oriented programming, and this book has a good, like its name, if you don't have the time and patience to read what you already know, the starting position of each chapter Both introduce the content of this chapter. Some basic knowledge is mainly introduced here. Understand the programming style of java, it is estimated that it is for users of other programming languages.
Interfaces and lambda expressions are introduced in Chapter 3 of the sample chapter. Some new features of interfaces and lambdas are introduced here, and some of them have been said before. An interface can add two methods with concrete implementations, static methods and default methods. The book gives many simple and easy-to-understand examples. A very valuable property of functional interfaces is that they can be instantiated using lambdas. So the book introduces lambda expressions. The usage and application are introduced, and the purpose of using lambda expressions is to achieve delayed execution.

The content of this book is very practical, not as heavy as the core technology two volumes, and it is very efficient for programmers to quickly get started with java.