Java Variable Types: Definition Guide

In Java, variables can be categorized into the following types:

1. Basic data types include integer, floating-point, character, and boolean types, such as int, double, char, boolean, etc.
2. Data types that can be referenced: include classes, interfaces, arrays, etc.

The syntax for defining variables is:

<数据类型> <变量名> = <初始值>;

For example:

int num = 10; // 定义一个整型变量num，并初始化为10
double price = 29.99; // 定义一个浮点型变量price，并初始化为29.99
char grade = 'A'; // 定义一个字符型变量grade，并初始化为'A'
boolean flag = true; // 定义一个布尔型变量flag，并初始化为true

String name = "Alice"; // 定义一个引用数据类型变量name，并初始化为"Alice"