can class have empty definition of a method java code example

Example: java method

public class Main {
  public static void main(String args[]) {
    SayHi();
    
    int sum = AddNums(5, 6);
    System.out.println(sum);
  }
  
  public static void SayHi() { //This method has no return value
    System.out.println("Hi!");
  }
  
  public static int AddNums(int a, int b) { //This method has a return value
    return a + b;
}