How can a double variable be defined in Java?

In Java, you can use the keyword double to define a double-precision floating point variable. Here is the syntax for defining a double variable:

double 变量名;

For example, the following code defines a double variable named number:

double number;

You can also initialize the variable at the time of its definition, as shown below:

double number = 3.14;

In this way, the variable number will be initialized to 3.14.