1,
|
What is the result?
A The output is “Equal”
B The output in “Not Equal”
C An error at line 5 causes compilation to fall.
D The program executes but does not print a message.
答案是:C
2, 下列不正确的 Java 语言标识符是( )
A Sky
B $Computer
C for
D NULL
解析:C
3,假设如下代码中,若t1线程在t2线程启动之前已经完成启动。代码的输出是()
public static void main(String[]args)throws Exception {
final Object obj = new Object();
Thread t1 = new Thread() {
public void run() {
synchronized (obj) {
try {
obj.wait();
System.out.println("Thread 1 wake up.");
} catch (InterruptedException e) {
}
}
}
};
t1.start();
Thread.sleep(1000);//We assume thread 1 must start up within 1 sec.
Thread t2 = new Thread() {
public void run() {
synchronized (obj) {
obj.notifyAll();
System.out.println("Thread 2 sent notify.");
}
}
};
t2.start();
A Thread 1 wake up Thread 2 sent notify.
B Thread 2 sent notify. Thread 1 wake up
C A、B皆有可能
D 程序无输出卡死
解析:B
4,@SuppressWarnings(“deprecation”)的功能是什么?
A 屏蔽不赞同使用的类和方法的警告
B 屏蔽在强制类型转换的时候编译器给出的警告
C 关闭所有警告信息
D 当在可序列化的类上缺少serialVersionUID定义的警告
解析:A