Java Programming Basics: Learn the core knowledge of the Java language

Java Programming Basics: Learn the core knowledge of the Java language

Java is an object-oriented programming language, which has become one of the important tools for many companies to write Web applications and services. In order to master Java programming, you need to master its core concepts and syntax, which are covered in the basics. In this article, we will introduce the core knowledge of Java programming.

1. Data type

In Java, data types are used to define variables and control the memory size and representation range of variables. There are 8 basic data types in Java, divided into primitive data types and reference data types. The primitive data types include boolean, byte, short, int, long, float, double and char. Reference data types include objects, arrays, and strings.

2. Variables and constants

In Java, variables and constants are identifiers used to represent data. Variables represent data that can be changed, and constants represent data that cannot be changed. Variables need to be declared and initialized, and constants need to be initialized when declared. In Java, the final keyword is generally used to define constants.

3. Operator

Operator is a symbol used to perform mathematical and logical operations. There are many kinds of operators in Java, such as arithmetic operations, comparison operations, and logical operations. wait. Use operators to process data and obtain results.

4. Control flow statements

Control flow statements are used to control the execution sequence of the program. There are three types of control flow statements in Java: conditional statements, loop statements and jumps statement. Conditional statements control the execution flow of the program based on the judgment of conditions; loop statements can repeatedly execute a section of code until a specific condition is met; jump statements transfer program control to a specified statement.

5. Method

A method is a programming structure in Java that is used to perform a specific task or complete a specific function. Methods can pass parameters and return values, and can be overloaded and overridden. Methods in Java are one of the cores of object-oriented programming, which can help programmers write maintainable, reusable and easily extensible code.

6. Classes and Objects

A class is a template or blueprint that defines an object in Java. It contains properties (fields) and methods. An object is an instantiation of a class and can access the properties and methods of the class. In Java, all classes inherit from the Object class, which contains basic operations such as equals and hashcode.

7. Inheritance and Polymorphism

Inheritance and polymorphism are two core concepts of object-oriented programming in Java. Inheritance means that one class is derived from another class and can inherit the properties and methods defined in another class. Polymorphism means that an object can exhibit different behaviors in different contexts. In Java, inheritance and polymorphism help programmers reuse and extend code.

Summary

In this article, we introduced the core knowledge of Java programming, including data types, variables and constants, operators, control flow statements, methods, classes and objects, as well as inheritance and multiple state. This knowledge is the basis of Java programming and a necessary condition for learning the Java language. If you want to become a Java programmer, you need to master this knowledge in depth and continue to accumulate practical experience.

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