目标：定义一个Producer类创建Student并添加到studnts集合中，再定义一个Consumer类从studnts集合中取出数据并打印控制台。Producer，Consumer类都实现了Runnable接口。
在MainTest类的main方法中创建线程并启动，如下所示：
Producer p = new Producer();
Thread tp1 = new Thread(p);
tp1.start();
Consumer c = new Consumer();
Thread tc1 = new Thread(c);
tc1.start();
这个时候，当tc1线程要执行的时候就报java.util.ConcurrentModificationException错误，我本是对线程调用这一块儿不是太明白。请大侠们帮我解决一下儿，请告诉我问啥会出这样的问题。
具体类如下所示：
Student类：一个普通类，其中定义了一个name属性和一个age属性。
public class Student {
private String name;
private String age;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAge() {
return age;
}
public void setAge(String age) {
this.age = age;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((age == null) ? 0 : age.hashCode());
result = prime * result + ((name == null) ? 0 : name.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Student other = (Student) obj;
if (age == null) {
if (other.age != null)
return false;
} else if (!age.equals(other.age))
return false;
if (name == null) {
if (other.name != null)
return false;
} else if (!name.equals(other.name))
return false;
return true;
}
}
Classroom接口：其中定义了一个名称为studnts的List用于存放Student对象。
public interface Classroom {
List<Student> studnts = new ArrayList<Student>();
}
State抽象类：其中定义了一个状态，想用这个对studnts集合的操作进行控制。
public abstract class State {
boolean state=true;
}
Producer类：添加Student到studnts中。
public class Producer extends State implements Runnable, Classroom {
private int i=0;
@Override
public void run() {
while(true) {
if(i<10) {
saveStudent();
}
}
}
public synchronized void saveStudent() {
if(!state) {
try {
wait();
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
Student s = new Student();
s.setName("name"+i);
s.setAge("age"+i++);
studnts.add(s);
System.out.println(Thread.currentThread().getName()+" --- Add Student "+s.getName()+" -- "+s.getAge());
state=true;
notify();
}
}
Consumer类：从studnts中取出strut对象并打印出来。
public class Consumer extends State implements Runnable, Classroom {
@Override
public void run() {
while(true) {
getStudent();
}
}
public synchronized void getStudent() {
if(!state) {
try {
wait();
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
for(Student s : studnts) {
System.out.println(Thread.currentThread().getName()+" --- get Stduent "+s.getName()+" --- "+s.getAge());
}
state = false;
notify();
}
}
