Forked Java VM 异常退出。JUnit 测试？

Forked Java VM exited abnormally. JUnit Test?

提问by user2092509

I have a simple Java program that seems to work well until uploaded to my school's grading system, "WebCat", which I'm assuming is just running JUnit. The error it kicks back is:

我有一个简单的 Java 程序，它在上传到我学校的评分系统“WebCat”之前似乎运行良好，我假设它只是运行 JUnit。它踢回来的错误是：

Forked Java VM exited abnormally. Please note the time in the report does not reflect the >time until the VM exit.

Forked Java VM 异常退出。请注意，报告中的时间不反映 VM 退出之前的时间。

I've researched this issue and and the main first troubleshooting step seems to be to look at the dump log. Unfortunately I cannot do that in this case. I am really at a loss on how to begin to troubleshoot this considering the lack of feedback from the grading system and the lack of compile or run-time errors.

我已经研究过这个问题，主要的第一个故障排除步骤似乎是查看转储日志。不幸的是，在这种情况下我不能这样做。考虑到缺乏评分系统的反馈以及缺乏编译或运行时错误，我真的不知道如何开始解决这个问题。

Here is the code if anyone is familiar with this error or can at least give me some direction of where to begin troubleshooting. Much appreciated!

如果有人熟悉这个错误，或者至少可以给我一些从哪里开始故障排除的方向，这里是代码。非常感激！

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.util.Scanner;
import java.io.IOException;



class PlayerApp {
    public static void showMenu()
    {
        System.out.println("Player App Menu");
        System.out.println("P - Print Report");
        System.out.println("A - Add Score");
        System.out.println("D - Delete Score");
        System.out.println("L - Find Lowest Score");
        System.out.println("H - Find Highest Score");
        System.out.println("Q - Quit");
    }
    public static void main(String[] args) throws IOException 
    {   
        if (args.length == 0)
        {
            System.out.println("File name was expected as a run argument.");
            System.out.println("Program ending.");
            System.exit(0);
        }
        String fileName = args[0];
        Scanner sc = new Scanner(System.in);
        String stnew = "";
        boolean exit = false;
        Player p = null;
        double[] scoreList;

        File dbFile = new File(fileName);
        FileInputStream fis = new FileInputStream(fileName); 
        InputStreamReader inStream = new InputStreamReader(fis); 
        BufferedReader stdin = new BufferedReader(inStream);
       String name = stdin.readLine();
       stnew = stdin.readLine();
       int numScore = Integer.parseInt(stnew);
       scoreList = new double[numScore];
       for (int i = 0; i < numScore; i++)
       {
          stnew = stdin.readLine();
          scoreList[i] = Double.parseDouble(stnew);
       }

       p = new Player(name, numScore, scoreList);

       stdin.close();

        System.out.println("File read in and Player object created.");
       showMenu();
       while (exit == false)
       {

        System.out.print("\nEnter Code [P, A, D, L, H, or Q]:");
        String choice = sc.nextLine().toLowerCase();
        if (choice.equals("p"))
        {
            System.out.println(p.toString());
        }
        else if (choice.equals("a"))
        {
            System.out.print("   Score to add: ");
            stnew = sc.nextLine();
            double scoreIn = Double.parseDouble(stnew);
            p.addScore(scoreIn);
        }
        else if (choice.equals("d"))
        {
            System.out.print("   Score to delete: ");
            stnew = sc.nextLine();
            double scoreIn = Double.parseDouble(stnew);
            p.deleteScore(scoreIn);
            System.out.println("   Score removed.");
        }
        else if (choice.equals("l"))
        {
            System.out.println("   Lowest score: " + p.findLowestScore());
        }
        else if (choice.equals("h"))
        {
            System.out.println("   Highest score: " + p.findHighestScore());
        }
        else if (choice.equals("q"))
        {
            exit = true;
        }
        }


   }
}

break

休息

import java.text.DecimalFormat;



public class Player {

    //Variables
    private String name;
    private int numOfScores;
    private double[] scores = new double[numOfScores];

    //Constructor
    public Player(String nameIn, int numOfScoresIn, double[] scoresIn) {
       name = nameIn;
       numOfScores = numOfScoresIn;
       scores = scoresIn;
   }

    //Methods
    public String getName() {
       return name;
    }
    public double[] getScores() {
       return scores;
    }
    public int getNumScores() {
       return numOfScores;
    }
    public String toString() {

        String res = "";
        DecimalFormat twoDForm = new DecimalFormat("#,###.0#");
      DecimalFormat twoEForm = new DecimalFormat("0.0");
        res += "   Player Name: " + name + "\n   Scores: ";
        for (int i = 0; i < numOfScores; i++)
        {
            res += twoDForm.format(scores[i]) + " ";
        }
        res += "\n   Average Score: ";
        res += twoEForm.format(this.computeAvgScore());
        return res;
    }
    public void addScore(double scoreIn) {
       double newScores[] = new double[numOfScores +1 ];
       for (int i = 0; i < numOfScores; i++)
       {
           newScores[i] = scores[i];
       }
       scores = new double[numOfScores + 1];
       for(int i = 0; i < numOfScores; i++)
       {
           scores[i] = newScores[i];
       }
       scores[numOfScores] = scoreIn;
       numOfScores++;
    }
    public boolean deleteScore(double scoreIn) {
        boolean found = false; 
        int index = 0;
        for (int i = 0; i < numOfScores; i++)
        {
           if (scores[i] == scoreIn)
            {
                found = true;
                index = i;
            }
        }
        if (found == true)
        {
            double newScores[] = new double[numOfScores -1 ];
            for (int i = 0; i < index; i++)
            {
               newScores[i] = scores[i];
            }
            for (int i = index + 1; i < numOfScores; i++)
            {
                newScores[i - 1] = scores[i];
            }
            scores = new double[numOfScores - 1];
            numOfScores--;
            for (int i = 0; i < numOfScores; i++)
            {
                scores[i] = newScores[i];
            }
            return true;
        }
        else
        {
            return false;
        }


    }
    public void increaseScoresCapacity() 
    {
        scores = new double[numOfScores + 1];
        numOfScores++;
    }
    public double findLowestScore() {
        double res = 100.0;
        for (int i = 0; i < numOfScores; i++)
        {
            if (scores[i] < res)
            {
                res = scores[i];
            }
        }
        return res;
    }
    public double findHighestScore() {
        double res = 0.0;
        for (int i = 0; i < numOfScores; i++)
        {
            if (scores[i] > res)
            {
                res = scores[i];
            }
        }
        return res;
    }
    public double computeAvgScore() {
        double res = 0.0;
      if (numOfScores > 0) {
           for (int i = 0; i < numOfScores; i++)
        {
               res += scores[i];
           }
           return res / (double)(numOfScores);
      }
      else {
         //res = 0.0;
         return res;
      }
    }

}

回答by Ernest Friedman-Hill

Your program is calling System.exit(0)for certain inputs. Don't do that! That's exactly what the message is telling you: that the JVM exited in the middle of the text, before the scoring code could finish up. Instead of calling exit(), just use returnto return from main()early.

您的程序需要System.exit(0)某些输入。不要那样做！这正是消息告诉您的内容：在评分代码完成之前，JVM 在文本中间退出。而不是调用exit()，只是用于早点return返回main()。

回答by Stefan Birkner

The library System Ruleshas a JUnit rule called ExpectedSystemExit. With this rule you are able to test code, that calls System.exit(...).

库系统规则有一个名为ExpectedSystemExit的 JUnit 规则。使用此规则，您可以测试调用 System.exit(...) 的代码。