为什么 Java 在让用户输入 String 的值之前强制我初始化 String？

问：

我本质上是在制作一个小型的、简单的“二十个问题”风格的程序，使用嵌套的 if 语句来尝试根据澄清问题来猜测用户在想什么对象。 我使用 if 语句最终在最后给用户一个“结果”，使用一个名为“result”的 String 变量。

我最终的困惑在于编译器声明“”。对此，根据代码，我认为它是在 if 语句之后。variable response may have not been initialized

import java.util.Scanner;

public class TwoQuestions {
  public static void main (String args[] ) {

    Scanner kb = new Scanner(System.in);

    String answer1, answer2, response;

    System.out.println("\n[Two Questions]\nThink of an object, and I'll try to guess it.");
    System.out.println("Is it an \"animal\", a \"vegetable\", or a \"mineral\"? (Type an answer exactly as quoted)");
    answer1 = kb.nextLine();
    System.out.println("Is it bigger than a breadbox? (yes/no)");
    answer2 = kb.nextLine();

    // example "response" based on user decisions
    if (answer1 == "animal" || answer1 == "Animal") {
      response = "yes";
      if (answer2 == "yes" || answer2 == "Yes") {
        response = "squirrel";
      }
    }
    // more if statements...

    // final machine "response" to user"
    // TODO: Figure out why *this* "response" requires initialization before if statements.
    System.out.println("My guess is that you are thinking of a " + response + ".\nI would ask you if I'm right, but I don't actually care.");

  }
}