Why else statement work when if statement is true in java

When I give a valid value it writes else statement(value is not valid to. And when I give a invalid value it writes else statement twice. I cant understand why its woking like that. Can someone help me?

    public  boolean isValid(int hour, int minute){
     if(!(hour>=0 && hour<=23))
      return false;
     if(!(minute>=0 && minute <=59))
      return false;
      return true;
  }

  public void setTime(int hour, int minute){
    if(isValid(hour,minute)){
      this.hour=hour;
      this.minute=minute;
    }
    else
      System.out.println("Values are not valid");
    }