由于Code，Eclipse表达式错误

Question

昨天它工作正常，但是现在Eclipse中的“表达式”窗格在调试时不会显示任何有用的信息，但会给出照片中显示的错误。我四处寻找答案，但找不到任何有用的东西。有谁知道如何解决这一问题？我尝试调试一个不同的程序，然后它工作，所以它必须与我的代码（？）有关。

详细说明：

• Eclipse Helios
• HP635笔记本电脑上的Windows 7
• 变量DO存在，如变量窗格
中所示
• 重启Eclipse无济于事
• 重新启动计算机无济于事
• 关闭并重新打开表达式窗格无效
• 清除表达式窗格无效

我的代码：

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;


public class Driver {

    private List<Integer>[] duplicateLists = new ArrayList[5];
    private List<Integer>[] lists = new ArrayList[5];

    private final int NUM_ALGORITHMS = 5;

    private boolean flag = false; //testing only
    private int calls = 0; // testing only

    public static void main(String[] args) {
        new Driver().run();
    }


    private void run() {
        printHeaders();
        createLists();
        for (int i = 0; i < NUM_ALGORITHMS; ++i) {
            resetDuplicates();
            switch (i) {
            case 0:
                System.out.print("|               | In order      |");
                System.out.println(selectionSort(duplicateLists[0]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Reverse Order |");
                System.out.println(selectionSort(duplicateLists[1]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|   SELECTION   | Random 1      |");
                System.out.println(selectionSort(duplicateLists[2]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Random 2      |");
                System.out.println(selectionSort(duplicateLists[3]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Partial Order |");
                System.out.println(selectionSort(duplicateLists[4]));
                System.out.println("+===============+===============+===============+===============+===============+");
                break;
            case 1:
                System.out.print("|               | In order      |");
                System.out.println(insertionSort(duplicateLists[0]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Reverse Order |");
                System.out.println(insertionSort(duplicateLists[1]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|   INSERTION   | Random 1      |");
                System.out.println(insertionSort(duplicateLists[2]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Random 2      |");
                System.out.println(insertionSort(duplicateLists[3]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Partial Order |");
                System.out.println(insertionSort(duplicateLists[4]));
                System.out.println("+===============+===============+===============+===============+===============+");
                break;
            case 2:
                System.out.print("|               | In order      |");
                System.out.println(bubbleSort(duplicateLists[0]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Reverse Order |");
                System.out.println(bubbleSort(duplicateLists[1]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|    BUBBLE     | Random 1      |");
                System.out.println(bubbleSort(duplicateLists[2]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Random 2      |");
                System.out.println(bubbleSort(duplicateLists[3]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Partial Order |");
                System.out.println(bubbleSort(duplicateLists[4]));
                System.out.println("+===============+===============+===============+===============+===============+");
                break;
            case 3:
                System.out.print("|               | In order      |");
                System.out.println(mergeSort(duplicateLists[0]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Reverse Order |");
                System.out.println(mergeSort(duplicateLists[1]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|     MERGE     | Random 1      |");
flag = true;
                System.out.println(mergeSort(duplicateLists[2]));
flag = false;
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Random 2      |");
                System.out.println(mergeSort(duplicateLists[3]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Partial Order |");
                System.out.println(mergeSort(duplicateLists[4]));
                System.out.println("+===============+===============+===============+===============+===============+");
                break;
            case 4:
                System.out.print("|               | In order      |");
                System.out.println(quicksort(duplicateLists[0]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Reverse Order |");
                System.out.println(quicksort(duplicateLists[1]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|   QUICKSORT   | Random 1      |");
                System.out.println(quicksort(duplicateLists[2]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Random 2      |");
                System.out.println(quicksort(duplicateLists[3]));
                System.out.println("|               |---------------+---------------+---------------+---------------+");
                System.out.print("|               | Partial Order |");
                System.out.println(quicksort(duplicateLists[4]));
                System.out.println("+===============+===============+===============+===============+===============+");
                break;
            }
        }
        System.out.println("CALLS: " + calls); //testing only
    }


    private ArrayList<Integer> createList(String path) {
        ArrayList<Integer> list = new ArrayList<Integer>();
        BufferedReader rd;
        try {
            rd = new BufferedReader(new FileReader(path));
            String line;
            while ((line = rd.readLine()) != null) {
                list.add(new Integer(Integer.parseInt(line)));
            }
            rd.close();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (NumberFormatException e) { 
        }
        return list;
    }


    private <T extends Comparable<? super T>> Data selectionSort(List<T> l) {
        int compares = 0;
        int swaps = 0;
        double time = System.nanoTime();
        for (int i = 0; i < l.size()-1; ++i) {
            int minIndex = i;
            for (int j = i+1; j < l.size(); ++j) {
                if (l.get(j).compareTo(l.get(minIndex)) < 0) {
                    minIndex = j;
                }
                ++compares;
            }
            if (minIndex != i) {
                swap(l, minIndex, i);
                ++swaps;
            }
        }
        time = (System.nanoTime() - time)/Math.pow(10, 9); // convert to seconds
        return new Data(l, time, compares, swaps, "Selection");
    } // method selectionSort


    private <T extends Comparable<? super T>> Data insertionSort(List<T> l) {
        int compares = 0;
        int swaps = 0;
        double time = System.nanoTime();
        for (int i = 1; i < l.size(); ++i) {
            for (int j = i; j > 0 && l.get(j-1).compareTo(l.get(j)) > 0; --j) {
                ++compares; // once during every loop
                swap(l, j, j-1);
                ++swaps;
            }
            ++compares; // one to correspond to final check
        }
        time = (System.nanoTime() - time)/Math.pow(10, 9); // convert to seconds
        return new Data(l, time, compares, swaps, "Insertion");
    } // method insertionSort


    private <T extends Comparable<? super T>> Data bubbleSort(List<T> l) {
        int compares = 0;
        int swaps = 0;
        double time = System.nanoTime();

        int finalIndex = l.size()-1;
        int swapIndex;

        while (finalIndex > 0) {
            swapIndex = 0;
            for (int i = 0; i < finalIndex; ++i) {
                if (((T)l.get(i)).compareTo(l.get(i+1)) > 0) { // if l[i] > l[i+1]
                    swap(l, i, i+1);
                    swapIndex = i;
                    ++swaps;
                }
                ++compares;
            }
            finalIndex = swapIndex;
        }
        time = (System.nanoTime() - time)/Math.pow(10, 9); // convert to seconds
        return new Data(l, time, compares, swaps, "Bubble");
    } // method bubbleSort


    private <T extends Comparable<? super T>> Data mergeSort(List<T> l) {
        double time = System.nanoTime();

        List<T> aux = (List<T>) ((ArrayList) l).clone();
        int compares = mergeSort(aux, l, 0, l.size());

        time = (System.nanoTime() - time)/Math.pow(10, 9); // convert to seconds
        return new Data(l, time, compares, 0, "Merge");
    } // method mergeSort 1 param


    private <T extends Comparable<? super T>> int mergeSort(List<T> src, List<T> dest, int low, int high) {

        if (flag) {
            calls++; // testing only
            System.out.println("PRE     SRC:  " + src);
            System.out.println("PRE     DEST: " + dest);
        }


        int compares = 0;

        int mid = (low + high) >> 1;
        if (high - low == 1) {

        } else {
            mergeSort(dest, src, 0, mid);
            mergeSort(dest, src, mid, high);
        }       
        for (int i = low, p = low, q = mid; i < high; ++i) {
            if (q >= high) {
                dest.set(i, src.get(p++));
            } else if (p >= mid){
                dest.set(i, src.get(q++));
            } else {
                if (((T)src.get(p)).compareTo(src.get(q)) <= 0) { 
                    dest.set(i, src.get(p++));
                } else {
                    dest.set(i, src.get(q++));
                }
                ++compares;
            }
        }


        if (flag) {
            System.out.println("POST    SRC:  " + src);
            System.out.println("POST    DEST: " + dest);
        }
        return compares;
    } // method mergeSort 4 params


    private <T extends Comparable<? super T>> Data quicksort(List<T> l) {

        return null;
    } // method quicksort


    private <T> void swap(List<T> l, int index1, int index2) {
        T temp = l.get(index1);
        l.set(index1, l.get(index2));
        l.set(index2, temp);
    } // method swap


    private void printHeaders() {
        System.out.println("+===============+===============+===============+===============+===============+\n" +
                            "|               |               |     TIME      |    NUMBER     |     NUMBER    |\n" +
                            "|  SORT METHOD  |  WHICH ARRAY  |      TO       |      OF       |       OF      |\n" +
                            "|               |               |   COMPLETE    |   COMPARES    |     SWAPS     |\n" +
                            "+===============+===============+===============+===============+===============+" );
    }


    private void createLists() {
        lists[0] = createList("C:\\Users\\Jason\\Documents\\School\\College\\Individual Studies\\202Projects\\07\\order.txt");
        lists[1] = createList("C:\\Users\\Jason\\Documents\\School\\College\\Individual Studies\\202Projects\\07\\reverse.txt");
        lists[2] = createList("C:\\Users\\Jason\\Documents\\School\\College\\Individual Studies\\202Projects\\07\\random1.txt");
        lists[3] = createList("C:\\Users\\Jason\\Documents\\School\\College\\Individual Studies\\202Projects\\07\\random2.txt");
        lists[4] = createList("C:\\Users\\Jason\\Documents\\School\\College\\Individual Studies\\202Projects\\07\\partial.txt");
    }


    private void resetDuplicates() {
        for (int i = 0; i < duplicateLists.length; i++) {
            if (duplicateLists[i] != null) {
                duplicateLists[i].clear();
            } else {
                duplicateLists[i] = new ArrayList<Integer>();
            }
            for (int j = 0; j < lists[i].size(); j++) {
                duplicateLists[i].add(new Integer(lists[i].get(j)));
            }
        }

    }

}

数据类：

import java.util.List;


public class Data {
    private List list;
    private double time;
    private int compares;
    private int swaps;
    private String name;


    public Data(List list, double time, int compares, int swaps, String name) {
        this.list = list;
        this.time = time;
        this.compares = compares;
        this.swaps = swaps;
        this.name = name;
    }


    public List getList() {
        return list;
    }


    public double getTime() {
        return time;
    }


    public int getCompares() {
        return compares;
    }


    public int getSwaps() {
        return swaps;
    }


    public String getName() {
        return name;
    }


    public String toString() {
        String timeString = String.format("%-14.4f", time);
        String compareString = String.format("%-14d", compares);
        String swapString = String.format("%-14d", swaps);

        return " " + timeString + "| " + compareString + "| " + swapString + "| " + list;
    }
}

Answer 1

这不是因为你的java代码。 “表达式”选项卡将显示变量的值。

但是调试指针位于类的第一行，现在甚至不存在这样的变量。

继续调试，一旦你越过创建变量的代码行，你就可以在表达式viewm中看到那里的值