全国软考程序员考试部分例题1

例题1：

Choose the three valid identifiers from those listed below.

A. IDoLikeTheLongNameClass B. $byte C. const D. _ok E. 3_case 解答：A, B, D

点评：Java中的标示符必须是字母、美元符($)或下划线(_)开头。关键字与保留字不能作为标示符。选项C中的const是Java的保留字，所以不能作标示符。选项E中的3_case以数字开头，违反了Java的规则。

例题2：

How can you force garbage collection of an object? A. Garbage collection cannot be forced B. Call System.gc().

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C. Call System.gc(), passing in a reference to the object to be garbage collected.

D. Call Runtime.gc().

E. Set all references to the object to new values（null, for example）.

解答：A

点评：在Java中垃圾收集是不能被强迫立即执行的。调用System.gc()或Runtime.gc()静态方法不能保证垃圾收集器的立即执行，因为，也许存在着更高优先级的线程。所以选项B、D不正确。选项C的错误在于，System.gc()方法是不接受参数的。选项E中的方法可以使对象在下次垃圾收集器运行时被收集。

例题3：

Consider the following class: 1. class Test(int i) { 2. void test(int i) {

3. System.out.println(“I am an int.”); 4. }

5. void test(String s) {

6. System.out.println(“I am a string.”); 7. } 8.

9. public static void main(String args[]) {

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10. Test t=new Test(); 11. char ch=“y”; 12. t.test(ch); 13. } 14. }

Which of the statements below is true?(Choose one.) A. Line 5 will not compile, because void methods cannot be overridden.

B. Line 12 will not compile, because there is no version of test() that rakes a char argument.

C. The code will compile but will throw an exception at line 12.

D. The code will compile and produce the following output: I am an int.

E. The code will compile and produce the following output: I am a String.

解答：D

点评：在第12行，16位长的char型变量ch在编译时会自动转化为一个32位长的int型，并在运行时传给void test(int i)方法。

例题4：

Which of the following lines of code will compile without

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error？

A. int i=0; if (i) {

System.out.println(“ Hi”); } B.

boolean b=true; boolean b2=true; if(b==b2) {

System.out.println(“So true”); } C. int i=1; int j=2; if(i==1|| j==2)

Systationship? (Choose two) A. public interface Person { }

public class Employee extends Person{ }

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B. public interface Shape { }

public interface Rectandle extends Shape { } C. public interface Colorable { }

public class Shape implements Colorable { }

D. public class Species{ }

public class Animal{private Species species;} E. interface Component{ }

class Container implements Component{ private Component[] children; }

解答：D, E

点评： 在Java中代码重用有两种可能的方式，即组合（“has a”关系）和继承（“is a”关系）。“has a”关系是通过定义类的属性的方式实现的；而“is a”关系是通过类继承实现的。本例中选项A、B、C体现了“is a”关系；选项D、E体现了“has a”关系。

全国软考程序员考试部分例题1 相关内容:

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