First-read Java API

Learn to program, be sure to learn to view and read the API. The so-called APIs are pre-defined functions that provide the ability of applications and developers to access a set of routines based on a piece of software or hardware without having to access the source code or understand the details of internal work. Learning the API, especially the official API, helps to fundamentally understand how the program works.

In the process of reading the API:

1. Although the API is intended to provide a convenient tool, without the programmer to learn the lower things and repeat the wheel, but a certain degree of understanding of the function of the mechanism to help the overall grasp, which is very helpful in cross-language learning, because all the programming language is based on computer hardware and system functions, The difference between different languages lies in the way of expression and implementation logic.

2. Read the API must read the original English, this is because the Chinese translation version can not completely translate the original meaning. Although in the beginning, there will be grammatical and semantic errors, but in the subsequent learning will gradually become proficient. and mastering good English reading ability is the necessary ability to learn and communicate cutting-edge technology.

3. Focus on the exercise of reading ability and understanding of the working mechanism, a language is often profound, knowledge points are difficult to master, it is almost impossible to remember all the functions, not to mention over time, if not used frequently, memory will become more and more blurred. Therefore, it is a very important ability to search for information in a long period of work and study life.

4. The Read API helps to connect the underlying concepts to form a knowledge network.

The Java version I'm using now is 1.8, open the API documentation on the website.

5. To read repeatedly, one is to improve reading ability, second, every reading will have a new discovery-new use scenes or notes.

What does a shallow read string function read?

1. Read the class name and package name, as well as the inherited classes and implemented interfaces

 Public Final class extends Implements Serializable,
Comparable<string>, charsequence

The String class is-java.lang.string under the directory named Lang, which inherits the object class and implements the Serializable,comparable<string>,charsequence three interfaces.

2. Read the example

String str = "abc"; // equivalent to: char data[] = {' A ', ' B ', ' C 'new  String (data); // Other Examples: SYSTEM.OUT.PRINTLN ("abc"= "CDE"; SYSTEM.OUT.PRINTLN ("abc" += "abc". SUBSTRING (2,3= cde.substring);

3. Reading methods

There is no return, return type;

There are no parameters, parameter types.

First-read Java API