JAVA面试题-深圳易思博

JAVA开发工程师面试题（一）备注：请不要在试卷上打草稿！请将答案填在答题纸上，100分钟内完成1.根据这个类选择所有正确的内部类：（多选）ABCclass A {protected int i;A(int i){this .i=i;}}a. class B{ }b.class B extends A{}c.class B{B(){System.out.println("i ="+i);}}d.class B{classA{}}e.class A{}2.下列所给出的声明中，什么会写入标准输出中？（单选）DSystem.out.println(4 | 7)?a. 4b. 5c. 6d. 7e. 03.下列有关方法notify()（用于和wait()连接）的正确描述是：（单选）Aa. if there is more than one thread waiting on a condition, only the thread that has been waiting the longest is notified.b. if there is more than one thread waiting on a condition, there is no way to predict which thread will be notified.c. Notify () is defined in the Thread class.d. It is not strictly necessary to own the lock for the object you invoke notify () for.e. Notify () should only be invoked from within a while loop.4.给出下列类的定义，如没有其他实例的引用，method2()能直接访问到：（多选）Aclass A{public int x;private int y;class B{protected void method1(){}class C{private void method2(){}}}}class d extends A{public float z;}a. The variable x defined in Ab. The variable y defined in Ac. method () defined in Bd. The variable z defined in D5.你有一个用ISO 8859－8定义的8位字符串文档，当你要在文本域中写一个显示该文档的应用，而局部编码已经设置成ISO 8859－8时，你如何写一段代码来读取该文档的第一行？（你有3个可获取的变量）a. InputStreamReader reader = new InputStreamReader(stream,"8859-8");BufferedReader buffer = new BufferedReader(reader);s = buffer.readLine();b. InputStreamReader reader = new InputStreamReader(stream);BufferedReader buffer = new BufferedReader(reader);s = buffer.readLine();c.InputStreamReader reader = new InputStreamReader(myfile,"8859-8");BufferedReader buffer = new BufferedReader(reader);s = buffer.readLine();d.InputStreamReader reader = new InputStreamReader(myfile);BufferedReader buffer = new BufferedReader(reader);s = buffer.readLine();e.FileReader reader = new FileReader(myfile);BufferedReader buffer = new BufferedReader(reader);s = buffer.readLine();6.哪一个对单机程序中的main()方法的声明是错误的？（多选）DEa. public static void main()b. public static void main(String[] string)c. public static void main(string args)d. static public int main(String[] args)e.static void main(String[] args)7.作为文本框对象的listeners，你可以添加哪一个执行接口？（多选）ABa. ActionListenerb. FocusListenerc. MouseMotionListenerd. WindowListenere. ContainerListener8.当你试着编译和运行下面的程序时，结果怎样？（单选）Eclass MyTest{String s;public static void main(String[] args){MyTest m = new MyTest();m.go();}void MyTest(){s = "constructor";}void go(){System.out.println(s);}a. This code will not compile.b. This code compiles but throws an exception at runtime.c. This code runs but nothing appears in the standard output.d. This code runs and "constructor" in the standard output.e. This code runs and writes "null" in the standard output.9.试分析以下两行代码：（多选）ACDfloat f = 3.2;int i = f;a. This code would not compile.b. This code would compile and i would be set to 3.c. The second line would compile if it were written instead as: int i = (byte)if;d. The first line would compile if it were written instead as: float f = 3.2F;在下面init()方法给出的applet中，用户接口将出现什么情况?（单选）CsetLayout(new BorderLayout());add (new Button("hello"));}a. Nothing will appear in the applet.b. A button will appear in the applet set int the exact center.c. A button will appear in the applet along the top and centered horizontally.d. A button will appear in the top left corner.10.如果你在JDK1.2下想要用值将关键字联系起来，则以下哪个类位首选？（多选）BDa. Dictionaryb. HashT ablec. Propertiesd. HashMape. TreeMap11.定义一个名为Key的无继承类正确方法是？（单选）Ea. class Key{}b. abstract final class Key{}c. native class Key{}d. class Key{final;}e. final class Key{}12.下列哪一个能代表一个octal number?（单选）Da. 0x12b. 320c. 032d. (octal)2e. 1213.当你运行T ester2类时，将得到什么标准输出结果？（单选）Eclass Tester2{int var;Tester(double var){this.var = (int)var;}Tester(int var){this("hello");Tester(String s){this();System.out.println(s);}Tester(){System.out.println("good-bye");}public static void main(String[] args){Tester t = new Tester(5);}}a. nothingb. "hello"c. 5d. "hello" following by "good-bye"e. "good-bye" followed by "hello"14.根据提供如下代码，如果方法tryThis() 发生一个NumberFormatException,将得到什么标准结果？（单选）try{ BtryThis();return;}catch(IOException x1){System.out.println("exception 1");return;}catch(Exception x2){System.out.println("exception 2");return;}finally{System.out.println("finally");}a. Nothingb. "exception 1" followed by "finally"c. "exception 2" followed by "finally"d. "exception 1"e. "exception 2"15.给出如下代码，如果此snippet在标准输出中显示为90，则method()调用了何种数学方法？（单选）C double a = 90.7;double b = method(a);System.out.println(b);a. absb. minc. floord. rounde. ceil16.如果"Ran.test"文档并不存在，而你试图编译并运行以下代码时，将会发生什么情况？（单选）Dimport java.io.*;class Ran{public static void main(String[] args) throws IOException{RandomAccessFile out = new RandomAccessFile("Ran.test","rw");out.writeBytes("Ninotchka");}}a. The code dose not compile because RandomAccessFile is not created correctly.b. The code dose not compile because RandomAccessFile dose not implement the writeBytes() method.c. The code compiles and runs but throws IOException because "Ran.test" does not yet exist.d. The code compiles and runs but nothing appears int the file "Ran.test" that it creates.e. The code compiles and runs and "Ninotchka" appears in the file "Ran.test" that it creates.17.当你创建一个新的线程时，如果提供一个目标对象，T argetObject是什么类型的实例才能作为合法参数传入：Thread t = new Thread(targetObject); Ca. targetObject instanceof Threadb. targetObject instandeof Objectc. targetObject instanceof Appletd. targetObject instanceof Runnablee. targetObject instanceof String18.给出如下的代码片断，哪一个表达式为合法的Java表达式，且返回值为真？（单选）：BBoolean b1 = new Boolean(true);Boolean b2 = new Boolean(true);a. b1 == b2b. b1.equals(b2)c. b1 & b2d. b1 | b2e. b1 && b2f. b1 || b219.下列哪一个布局管理器以从左至右，然后从上到下，以每一行为中心移动的方式排列组件？(单选）Ca. BorderLayoutb. FlowLayoutc. GridLayoutd. CardLayoute. GridBagLayout20.下列哪一个关于垃圾收集的描述是正确的？（多选）BCa. You can directly free the memory allocated by an object.b. You can directly run the garbage collector whenever you want to.c. The garbage collector informs your object when it is about to be garbage collected.d. The garbage collector reclaims an object's memory as soon as it becomes a candidate for garbage collection.e. The garbage collector runs in low-memory situations.21.Given this interface definition:根据该界面定义，下列哪一个类能实现该接口并且不是抽象类？（多选）interface A{int method1(int i);int method2(int j);}class B implements A{ int method1(){}int method2(){}} b. class B {int method1(inti){}int method2(intj){}}c. class Bimplements A{int method1(inti){}int method2(intj){}}d. class B extendsA{int method1(inti){}int method2(intj){}}e. class B implementsA{int method1(int j){}int method2(int i){}}22.Examine the following switch block根据如下的转换流,下列哪个命题是正确的？（多选）BEchar mychar = 'c';switch (mychar){default:case 'a': System.out.println("a"); break;case 'b': System.out.println("b"); break;}a. This switch block is illegal, because only integers can be used in the switch statement.b. This switch block is fine.c. This switch block is illegal, because the default statement must come last.d. When this code runs, nothing is written to the standard output.e. When this code runs, the letter "a" is written to the standard output.23.如果你编译,运行以下类，将会出现什么情况？（单选）Cclass Test{static int myArg = 1;public static void main(String[] args){int myArg;System.out.println(myArg);}}a. This code compiles and displays 0 in the standard output when run.b. This code compiles and displays 1 in the standard output when run.c. This code does not compile because you cannot define a local variable named the same as a static variable.d. This code does not compile because the local variable is used before it is initialized.24.如果你用名为c的变量为引用组件调用addContainerListener()函数，请估计下列哪个表达式将为这个问题提出正确或错误的回答？（单选）Ca. c == Containerb. c.equals(Class.Container)c. c instanceof Containerd. c instanceof Componente. c implements Container25.当下列程序运行“java Mystery Mighty Mouse”命令时将得到什么结果？（单选）Ajava Mystery Mighty Mouseclass Mystery{public static void main(String[] args){Changer c = new Changer();c.method(args);System.out.println(args[0] + " " + args[1]);}static class Changer{void method(String[] s){String temp = s[0];s[0] = s[1];s[1] = temp;}}}a. This program causes an ArrayIndexOutOfBoundsException to be thrown.b. This program runs but does not write anything to the standard output.c. This program writes "Myighty Mouse" to the standard output.d. This program writes "Mouse Myighty" to the standard output.26.根据提供的如下代码，请问在//A处应该补充什么代码该程序可以标准输出单词‘running’？(单选)C class RunTest implements Runnable{public static void main(String[] args){RunTest rt = new RunTest();Thread t = new Thread(rt);//A}public void run(){Systme.out.println("running");}void go(){start(1);}void start(int i){}}a. System.out.println("running");b. rt.start();c. rt.go();d. rt.start(1);27.分析下面的一行代码，选择一个正确的回答（单选Aif(5 & 7 > 0 && 5 | 2) System.out.println("true");a. This line of code will not compile.b. This code will compile but nothing will appear in the standard output.c. This code will compile and write the word "true" in the standard output.28.请选出有关在Component类中定义的paint()方法所有正确的描述：（单选）Ba. It is protected.b. It takes an instance of class Graphics.c. It is static.d. It is invoked automatically whenever you minimize and then maximize a component, such as a window.e. There is also a version that takes an int.29.分析以下代码，选择所有正确的答案。