関連ワード:  why we use main method in java    why we need main method in java    why we use main function in java    why we use static in main method in java    why we use void in main method in java    why we use string in main method in java    why we use public in main method in java    why we use static keyword in main method in java    why we use string args in main method in java    why we write main method in java