private Lock lock = new ReentrantLock(); public static void main(String[] args) { }
private class Subtractor implements Runnable { }
private class Adder implements Runnable {
@Override
public void run() {
// TODO Auto-generated method stub while(true) { @Override
public void run() { }
// TODO Auto-generated method stub while(true) { }
/*synchronized (ThreadTest.this) {
System.out.println(\ //这里抛异常了，锁能释放吗？ }*/
lock.lock(); try { { }
lock.unlock();
System.out.println(\}finally
// TODO Auto-generated method stub ThreadTest tt = new ThreadTest(); for(int i=0;i<2;i++) { }
new Thread(tt.new Adder()).start(); new Thread(tt.new Subtractor()).start();
/*synchronized (ThreadTest.this) { System.out.println(\ }*/
lock.lock(); try { System.out.println(\ }finally
{
lock.unlock();
}
}
}
}
}
55、设计4个线程，其中两个线程每次对j增加1，另外两个线程对j每次减少1。写出程序。
以下程序使用内部类实现线程，对j增减的时候没有考虑顺序问题。 public class ThreadTest1 {
private int j;
public static void main(String args[]){ ThreadTest1 tt=new ThreadTest1(); Inc inc=tt.new Inc(); Dec dec=tt.new Dec(); for(int i=0;i<2;i++){
Thread t=new Thread(inc); t.start();
t=new Thread(dec); t.start(); } }
private synchronized void inc(){ j++;
System.out.println(Thread.currentThread().getName()+\ }
private synchronized void dec(){ j--;
System.out.println(Thread.currentThread().getName()+\ }
class Inc implements Runnable{ public void run(){
for(int i=0;i<100;i++){ inc(); } } }
class Dec implements Runnable{ public void run(){
for(int i=0;i<100;i++){ dec(); } } } }
----------随手再写的一个------------- class A {
JManger j =new JManager(); main() {
new A().call(); }
void call {
for(int i=0;i<2;i++) {
new Thread( new Runnable(){ public void run(){while(true){j.accumulate()}}} ).start();
new Thread(new Runnable(){ public void run(){while(true){j.sub()}}}).start(); } } }
class JManager {
private j = 0;
public synchronized void subtract() { j--
}
public synchronized void accumulate() {
j++; } }
56、子线程循环10次，接着主线程循环100，接着又回到子线程循环10次，接着再回到主线程又循环100，如此循环50次，请写出程序。
最终的程序代码如下：
public class ThreadTest {
}
public void run() { }
for(int i=0;i<50;i++) {
business.SubThread(i);
}
public void init() {
final Business business = new Business(); new Thread(
new Runnable() {
} /**
* @param args */
public static void main(String[] args) {
// TODO Auto-generated method stub new ThreadTest().init();
}
).start();
for(int i=0;i<50;i++) {
business.MainThread(i);
}
private class Business {
boolean bShouldSub = true;//这里相当于定义了控制该谁执行的一个信号灯 public synchronized void MainThread(int i) { }
public synchronized void SubThread(int i) {
if(!bShouldSub)
try {
this.wait();
// TODO Auto-generated catch block e.printStackTrace();
} catch (InterruptedException e) { if(bShouldSub) { }
bShouldSub = true; this.notify();
System.out.println(Thread.currentThread().getName() + try {
this.wait();
// TODO Auto-generated catch block e.printStackTrace();
} catch (InterruptedException e) {
}
for(int j=0;j<5;j++)
\
}
for(int j=0;j<10;j++)
Java面试宝典2012版
