Variable Dynamic Initialization : Variables « Language « Java Tutorial

public class MainClass {
  public static void main(String args[]) {
    double a = 3.0, b = 4.0;

    // c is dynamically initialized
    double c = Math.sqrt(a * a + b * b);

    System.out.println("Hypotenuse is " + c);
  }
}

Hypotenuse is 5.0

1.9.Variables
	1.9.1.	Variables
	1.9.2.	Variable Dynamic Initialization
	1.9.3.	Demonstrate lifetime of a variable
	1.9.4.	shows the proper way to declare a class variable named helloMessage
	1.9.5.	You don't have to place class variable declarations at the beginning of a class.
	1.9.6.	helloMessage variable is declared as a local variable: