【计算机二级Java语言】卷005

选择题

公共知识

【10】有三个关系R、S和T如下:

则由关系R和S得到关系T的操作是()。

专业知识

        int i = 2, j = 6;
System.out.println((i + 5) > j);
    

        int i = 2, j = 4;
boolean k;
k = (i++) > 0 && (++j - 4) < 0;
System.out.println(i * j);
    

在Java中运算的优先级参照 。本题答案为D选项。

        public class Test {
    public static void main(String[] args) {
        int a = 3;
        double b = 3.5;
        int k = (int) b;
        if (a == k)
        System.out.println("0");
        else if (a > k)
        System.out.println("1");
        else
        System.out.println("2");
    }
}
    

        public class Test {
    public static void main(String[] args) {
        int i = 1;
        while (i < 7) {
            if (i % 2 == 0)
            System.out.print(i);
            i++;
        }
    }
}
    

        public class Test {
    public static void main(String[] args) {
        int count = 0;
        for (int i = 1 ; i < 5; i += 2)
        for (int j = 1 ; j <= 10; j += 3)
        count ++;
        System.out.print(count);
    }
}
    

        abstract class Person {
    public Person(String n) {
        name = n;
    }
    public ________ String getDescription();
    public String getName() {
        return name;
    }
    private String name;
}
    

        public class Test {
    String s = "One World One Dream";
    public static void main(String[] args) {
        System.out.println(s);
    }
}
    

        public void test() {
    try {
        sayHello();
        System.out.println("Hello");
        } catch(ArrayIndexOutOfBoundsException e) {
        System.out.println("ArrayIndexOutOfBoundsException ");
        } catch(Exception e) {
        System.out.println("Exception ");
        } finally {
        System.out.println("finally");
    }
}
    

        public class ConcatTest {
    public static void main(String[] args) {
        String str1 = "abc";
        String str2 = "ABC";
        String str3 = str1.concat(str2);
        System.out.println(str3);
    }
}
    

        public class Arrays {
    public static void main(String[] args) {
        int[] a = new int[5];
        for (int i = 0; i < a.length; i = i + 1) {
            a[i] = 10 + i;
        }
        for (int i = 0; i < a.length; i = i + 1) {
            System.out.print(a[i] + " ");
        }
        String[] s = {"Frank", "Bob", "Jim"};
        for (int i = 0; i < s.length; i = i + 1) {
            System.out.print(s[i] + " ");
        }
        s[2] = "Mike";
        System.out.print(s[2]);
    }
}
    

        ObjectOutputStream out = new ObjectOutputStream(new ____________("score.dat"));
out.writeObject(fenshu);
out.close();
    

        import java.io.*;
public class ObjectStreamTest {
    public static void main(String[] args) throws IOException {
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("serial.bin"));
        java.util.Date d = new java.util.Date();
        oos.____________(d);
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream("serial.bin"));
        try {
            java.util.Date restoredDate = (java.util.Date) ois.readObject();
            System.out.println("read Object back from serial.bin file: "+ restoredDate);
        }
        catch(ClassNotFoundException cnf) {
            System.out.println("class not found");
        }
    }
}
    

        class Employee implements __________ {
    ……
}
    

        public class Test2 ___________ {
    public static void main(String[] args) {
        Thread t = new Test2();
        t.start();
    }
    public void run() {
        System.out.println("How are you.");
    }
}
    

        public class ThreadTest {
    public static void main(String[] args) throws Exception {
        int i = 0;
        Hello t = new Hello();
        _____________________;
        while (true) {
            System.out.println("Good Morning"+i++);
            if (i == 2 && t.isAlive()) {
                System.out.println("Main waiting for Hello!");
                t.join();  //等待t运行结束
            }
            if (i == 5) break ;
        }
    }
}
class Hello extends Thread {
    int i ;
    public void run() {
        while (true) {
            System.out.println("Hello"+i++);
            if (i == 5) break ;
        }
    }
}
    

原文：https://www.cnblogs.com/mjios/p/12454967.html