1113中科方德笔试题.doc

中科方德笔试题1. Overload和Override的区别，Overloaded的方法是否可以改变返回值的类型。2. 接口是否可以继承接口？抽象类可否实现接口？抽象类可否继承实体？3. HashMap 和 HashTable 区别。4. String 和StringBuffer 区别。5. 排序有那几种方法，请举例。6. 检验登录名，只能输入5-20个以字母开头，可带数字、”_”、”.”的字串，请写出判断登录名是否正确的JavaScript正则表达式。7. 作用域 public private protected 以及不写时的区别。8. 下面程序是否有错，如果有错，错在哪里？public class Somethingpublic static void main(String args)Something s = new Something();System.out.println(s.doSomething() returns+doSomething();public String doSomething()return Do Something;9. 单选题 （）static void test throws RuntimeExceptiontrySystem.out.print(test);throw new RuntimeException();catch(Exception ex)System.out.print(exception);public static void main(String args)trytest();catch(RuntimeException ex)System.out.println(runtime);System.out.print(end);What is the result?A. test endB. Compilation failsC. test runtime endD. test exception endE. A throwable is thrown by main at runtime;10. 选择题 （）A class games.cards.Poker is correctly defined in the jar file Poker.jar . A user wants to execute the main method of Poker on a UNIX system using the command:java games.cards.PokerWhat allows the user to do this?A. put Poker.jar in directory/stuff/java, and set the CLASSPATH to include/stuff/javaB. put Poker.jar in directory/stuff/java, and set the CLASSPATH to include/stuff/java/*.jarC. put Poker.jar in directory/stuff/java, and set the CLASSPATH to include/stuff/java/Poker.jarD. put Poker.jar in directory/stuff/java/games/cards,and set the CLASSPATH to include/stuff/javaE. put Poker.jar in directory/stuff/java/games/cards,and set the CLASSPATH to include/stuff/*.javaF. put Poker.jar in directory/stuff/java/games/cards,and set the CLASSPATH to include/stuff/java/Poker.jar考题一下面代码输出结果是什么，存在什么问题，如何修改？public class MyClassprivate Integer id;private Double value;public MyClass(Integer id)this.id = id;value = Math.random();overridepublic boolean equals(Object obj)if(obj = null | !(obj instanceof MyClass)return false;MyClass myObj = (MyClass)obj;if(id = null | myObj.id = null)return false;return id.equals(myObj.id);public static void main(String args)Map objMap = new HashMap();MyClass objA = new MyClass(1);MyClass objB = new MyClass(2);objMap.put(objA, Im Object A);objMap.put(objB, Im Object B);MyClass objC = new MyClass(1);String result = objMap.get(objC);System.out.pritnln(result);考题二设键盘输入n个英语单词，输入格式为n，w1，w2，.，wn，其中n表示随后输入单词个数，试编一程序，建立一个单向链表，实现： （1）如果单词重复出现，则只在链表上保留一个。 （2）除满足（1）的要求外，链表结点还应有一个计数域，记录该单词重复出现的次数，然后输出出现次数最多的前K（K=n）个单词。考题三编写一个街区字符串的函数，输入为一个字符串和字节数，输入为按字节截取的字符串，但是要保证汉字不被截取半个。如“我ABC”、4，应该截为“我AB”，输入“我AB