Java 内存泄漏示例答案

【问题标题】：Java memory leak exampleJava 内存泄漏示例
【发布时间】：2015-02-18 18:14:20
【问题描述】：

我遇到了this article 关于内存泄漏。它说下面的代码有内存泄漏。但我不明白它是如何泄漏内存的。

import java.util.ArrayList;
 import java.util.List;
 import java.util.Iterator;
 import java.util.Random;


 public class MemoryLeak
 {
     // Generates long lines of gibberish words.
     static class GibberishGenerator implements Iterator<String>
     {
         private int MAX_WORD_LENGTH = 20;
         private int WORDS_PER_LINE = 250000;
         private String alphabet = ("abcdefghijklmnopqrstuvwxyz" +
                                    "ABCDEFGHIJKLMNOPQRSTUVWXYZ");

         public boolean hasNext() {
             return true;
         }

         public String next() {
             StringBuffer result = new StringBuffer();
             for (int i = 0; i < WORDS_PER_LINE; i++) {
                 if (i > 0) { result.append(" "); }
                 result.append(generateWord(MAX_WORD_LENGTH));
             }

             return result.toString();
         }

         public void remove() {
             // not implemented
         }


         private String generateWord(int maxLength) {
             int length = (int)(Math.random() * (maxLength - 1)) + 1;
             StringBuffer result = new StringBuffer(length);
             Random r = new Random();

             for (int i = 0; i < length; i++) {
                 result.append(alphabet.charAt(r.nextInt(alphabet.length())));
             }

             return result.toString();
         }
     }


     // A "good" word has as many vowels as consonants and is more than two
     // letters long.
     private static String vowels = "aeiouAEIOU";

     private static boolean isGoodWord(String word) {
         int vowelCount = 0;
         int consonantCount = 0;

         for (int i = 0; i < word.length(); i++) {
             if (vowels.indexOf(word.charAt(i)) >= 0) {
                 vowelCount++;
             } else {
                 consonantCount++;
             }
         }

         return (vowelCount > 2 && vowelCount == consonantCount);
     }


     public static void main(String[] args) {
         GibberishGenerator g = new GibberishGenerator();
         List<String> goodWords = new ArrayList<String>();

         for (int i = 0; i < 1000; i++) {
             String line = g.next();
             for (String word : line.split(" ")) {
                 if (isGoodWord(word)) {
                     goodWords.add(word);

                     System.out.println("Found a good word: " + word);
                     break;
                 }
             }
         }
     }
 }

完整文章请参考以下链接：
这里可能的内存泄漏是什么？StringBuffer 用于生成 Gibbersish 世界。

【问题讨论】：

标签： java string memory-leaks garbage-collection out-of-memory

【解决方案1】：

您应该继续阅读，它是添加到 goodWords 列表中的引用，如标题为 Spoiler 的部分中所述：

这是罪魁祸首：

String line = g.next();
for (String word : line.split(" ")) {
    if (isGoodWord(word)) {
        goodWords.add(word);

还有更多

更新：从 Java 1.7 更新 6 开始，字符串行为发生了变化，因此获取子字符串不会保留在原始字节数组中。这对我的人为示例造成了一点打击，但发现问题的总体方法仍然有效。

【讨论】：