（Java）即使if语句明确为true，程序也不会通过if语句

Question

我正在为我的CHS Java课程做一个项目，该项目为Monty Hall游戏节目建模。但是出于某种原因，即使是真的，这个if语句也不会“激活” ...有什么想法吗？

System.out.println("There is a goat behind Door #" + (goatSpot));   
System.out.println("Would you like to switch your door? (yes or no) ");
String switchChoice = input.next();
switchChoice = switchChoice.toUpperCase();
if (switchChoice == "YES")
{           
    if (choice == 1 && goatSpot == 2)
    {
        choice = 3;
    }
    else if (choice == 1 && goatSpot == 3)
    {
        choice = 2;
    }
    else if (choice == 2 && goatSpot == 3)
    {
        choice = 1;
    }
    else if (choice == 2 && goatSpot == 1)
    {
        choice = 3;
    }
    else if (choice == 3 && goatSpot == 1);
    {
        choice = 2;
    }
    if (choice == 3 && goatSpot == 2)
    {
        choice = 1;
    }
}

它只是完全忽略了if语句中的所有内容。...