Java 返回语句

如何使此代码正常工作？我需要返回3个场景中的语句，目前我在字符串robotInfo中遇到一个错误

String generateStatusReport(Robot robot) {

    String robotStatus;
    String robotWall;
    String robotGround;
    String robotInfo = robotStatus + robotWall + robotGround;

    if(isRobotDead(robot)) {
        robotStatus = ("The robot is dead.");
    } else {
        robotStatus = ("The robot is alive.");
        if(isRobotFacingWall(robot)) {
            robotWall = ("The robot is facing a wall.");
        } else {
            robotWall = ("The robot is not facing a wall.");
        }

        if(isItemOnGroundAtRobot(robot)) {
            robotGround = ("There is an item here.");
        } else {
            robotGround = ("There is no item here.");
        }
    }
    return robotInfo;
}

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您需要初始化字符串以获取robotInfo中的值

String robotStatus;
    String robotWall;
    String robotGround;

---

我会将连接移动到条件语句之后但返回语句之前：

String generateStatusReport(Robot robot) {

    String robotStatus;
    String robotWall;
    String robotGround;

    if(isRobotDead(robot))
        robotStatus = ("The robot is dead.");
    else {
        robotStatus = ("The robot is alive.");
        if(isRobotFacingWall(robot))
            robotWall = ("The robot is facing a wall.");
        else
            robotWall = ("The robot is not facing a wall.");

        if(isItemOnGroundAtRobot(robot))
            robotGround = ("There is an item here.");
        else
            robotGround = ("There is no item here.");
    }
    String robotInfo = robotStatus + robotWall + robotGround;
    return robotInfo;
}

或者只返回连接：

return robotStatus + robotWall + robotGround;