Java考试题+答案.docx

选择题（每题3分，共45分）1、下列程序编译或运行的结果是。（ ）D public static void main(String args[]){int a = 10;int b,c;if(a50){b=9;}c = b + a;System.out.println(c);}A.10 B. 19C.9 D.编译错误2、下列语句片段中，four的值为 ()Dint three = 3;char one = ‘1’;char four = (char)(three+one);A. 3B. 1C. 31D. 4 3、下列代码的运行结果是 ( )Dpublic static void main(String[] args){int a = 7;System.out.println(a%3);}A．2.0 B．2 C．1.0 D．14、以下程序的输出结果为( )。Dpublic static void main(String[]args) {int x = 1, y = 1, z =1;if(x--==1y--==1||z--==1)System.out.println(“x=” +x+”,y=” +y+”,z=” +z);} A.x=0, y=1,z=1 B.x=0,y=2,z=2 C.x=0,y=2,z=1 D.x=0,y=0,z=15、下列代码段编译和运行的结果是（）.Cpublic static void main(String args[]){String str = “null”;if(str==null){System.out.println(“null”);}else if(str.length()==0){System.out.println(“zero”);}else {System.out.println(“some”);}} A. null B. zero C. some D. 编译错误6、下列代码的运行结果是（）：Dpublic class Animal{public String noise(){return “peep”;}public static void main(String[] args){Animal animal = new Dog();Cat cat = (Cat)animal;System.out.println(cat.noise());}}class Dog extends Animal{public String noise(){return “bark”;}}class Cat extends Animal{public String noise(){return “meow”;}} A. peepB.barkC.meowD.编译错误E. 抛出运行时异常7、关于下列代码说法正确的是( )Dpublic class Foo{public int add(int a,int b){return a+b;}public static void main(String[] args){Foo foo = null;System.out.println(foo.add(10,20));}} A. 编译错误 B. 正常运行，但无结果输出 C.30 D.运行时抛出NullPointerException8、程序的执行结果是 ( )Bpublic class Test{int x;public static void main(String[] args){Test t = new Test();t.x = 5;change(t);System.out.println(t.x);}public static void change(Test t){t.x = 3;}} A. 5B. 3C. 0D. 49、关于下列代码书法正确的是 ( )Bpublic class A{public void doit(){}public String doit(){ return “a”;}public double doit(int x){ return 1.0;}}A. 无编译错误B. 代码public String doit(){行，出现编译错误C. 代码public double doit(int x){行，出现编译错误D. 代码return “a”;行处 出现编译错误10、下列代码的运行结果是（ ）DString test = “This is a test”;String[] tokens = test.split(“\\s”);System.out.println(tokens.lengt