/**   * 使用增強的for循環   * 在循環過程中從List中刪除元素以后，繼續循環List時會報ConcurrentModificationException   */  public void listRemove() {    List<Student> students = this.getStudents();    for (Student stu : students) {      if (stu.getId() == 2)         students.remove(stu);    }  }

/**   * 像這種使用增強的for循環對List進行遍歷刪除，但刪除之后馬上就跳出的也不會出現異常   */  public void listRemoveBreak() {    List<Student> students = this.getStudents();    for (Student stu : students) {      if (stu.getId() == 2) {        students.remove(stu);        break;      }    }  }

/**   * 這種遍歷有可能會遺漏某個元素,因為刪除元素后List的size在   * 變化，元素的索引也在變化，比如你循環到第2個元素的時候你把它刪了，   * 接下來你去訪問第3個元素，實際上訪問到的是原先的第4個元素。當訪問的元素   * 索引超過了當前的List的size后還會出現數組越界的異常，當然這里不會出現這種異常，   * 因為這里每遍歷一次都重新拿了一次當前List的size。   */  public void listRemove2() {    List<Student> students = this.getStudents();    for (int i=0; i<students.size(); i++) {      if (students.get(i).getId()%3 == 0) {        Student student = students.get(i);        students.remove(student);      }    }  }

/**   * 使用Iterator的方式也可以順利刪除和遍歷   */  public void iteratorRemove() {    List<Student> students = this.getStudents();    System.out.println(students);    Iterator<Student> stuIter = students.iterator();    while (stuIter.hasNext()) {      Student student = stuIter.next();      if (student.getId() % 2 == 0)//這里要使用Iterator的remove方法移除當前對象，如果使用List的remove方法，則同樣會出現ConcurrentModificationException        stuIter.remove();    }    System.out.println(students);  }

import java.util.ArrayList;import java.util.Iterator;import java.util.List;public class ListRemove {  public static void main(String args[]) {    ListRemove lr = new ListRemove();    lr.listRemove();    lr.listRemoveBreak();//    lr.listRemove2();//    lr.iteratorRemove();  }  /**   * 使用增強的for循環   * 在循環過程中從List中刪除元素以后，繼續循環List時會報ConcurrentModificationException   */  public void listRemove() {    List<Student> students = this.getStudents();    for (Student stu : students) {      if (stu.getId() == 2)         students.remove(stu);    }  }    /**   * 像這種使用增強的for循環對List進行遍歷刪除，但刪除之后馬上就跳出的也不會出現異常   */  public void listRemoveBreak() {    List<Student> students = this.getStudents();    for (Student stu : students) {      if (stu.getId() == 2) {        students.remove(stu);        break;      }    }  }    /**   * 這種不使用增強的for循環，每次重新獲取list的size遍歷的情況運行時不會報錯，但是可能刪除的結果是錯的。   */  public void listRemove2() {    List<Student> students = this.getStudents();    for (int i=0; i<students.size(); i++) {      if (students.get(i).getId()%2 == 0)        students.remove(i);    }  }    /**   * 使用Iterator的方式也可以順利刪除和遍歷   */  public void iteratorRemove() {    List<Student> students = this.getStudents();    System.out.println(students);    Iterator<Student> stuIter = students.iterator();    while (stuIter.hasNext()) {      Student student = stuIter.next();      if (student.getId() % 2 == 0)        stuIter.remove();    }    System.out.println(students);  }    private List<Student> getStudents() {    List<Student> students = new ArrayList<Student>() {      {        int i = 0;        while (i++ < 10) {          Student student = new Student(i, "201200" + i, "name_" + i);          this.add(student);        }      }    };    return students;  }}

public class Student {  private int id;  private String stuNo;  private String name;    public Student() {      }    public Student(int id, String stuNo, String name) {    this.id = id;    this.stuNo = stuNo;    this.name = name;  }  public int getId() {    return id;  }  public void setId(int id) {    this.id = id;  }  public String getStuNo() {    return stuNo;  }  public void setStuNo(String stuNo) {    this.stuNo = stuNo;  }  public String getName() {    return name;  }  public void setName(String name) {    this.name = name;  }  @Override  public String toString() {    return "Student [id=" + id + ", name=" + name + ", stuNo=" + stuNo        + "]";  }  }