真正最好的是将所有内容都放在一个类中，没有理由将一个类分成两个类，只是为了使获取器和设置器与其他类分开，这 没有任何意义
。我确实想知道您是否误解了您的作业。

import java.util.Scanner;
class shoppingApp
{
    //since it's an instance field not local to the class it's declared here instead of main
    static String orangeSelected = "";

    public static void main(String[] args)
    {
        //orange  selected is an odd name for a scanner, just use scan or something similar
        Scanner scan = new Scanner(System.in); //note that you were missing a semicolon
        System.out.println("Premium Oranges\n"); //include a new line or a space before asking for input, for example with \n
        orangeSelected = scan.nextLine();
    }
    //setter
    public static void setOrangeSelected(String str)
    {
        orangeSelected = str;
    }
    //getter
    public static String getOrangeSelected()
    {
        return orangeSelected;
    }

    //Note that all methods and instance fields are static because the main method must be static if you don't understand this yet that's ok.
}

现在，如果出于某种原因您绝对 必须 使用两个类，则它看起来应该像这样，尽管我会注意到，只是在不理解的情况下复制和粘贴我的代码将是 作弊行为 。

import java.util.Scanner;
class shoppingApp
{
    //normally this shouldn't be public
    public static String orangeSelected = "";

    public static void main(String[] args)
    {
        Scanner scan = new Scanner(System.in); 
        System.out.println("Premium Oranges\n");
        orangeSelected = scan.nextLine();
    }
}

 class gettersAndSetters
{
    //setter
    public void setOrangeSelected(String str)
    {
        Main.orangeSelected = str;
    }
    //getter
    public String getOrangeSelected()
    {
        return Main.orangeSelected;
    }
}