已知
import java.io.*;
class Person{
public static void print(){System.out.print("Person");}
}
class Employee extends Person{
public void print(){
System.out.prin
import java.io.*;
class Person{
public static void print(){System.out.print("Person");}
}
class Employee extends Person{
public void print(){
System.out.prin
以下文字与答案无关
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}
});
}
public void show(Car c){
c.run();
c.show();
}}
abstract class Car{
public void run(){
System.out.println("car run");
}
public void show(){
System.out.println(getClass().getName());
}}
">1.请写出以下程序运行结果:package test;
public class Test {
public static void main(String] args) {
Test t = new Test();
t.show(new Car(){
public void run(){
System.out.println("test run");
}
});
}
public void show(Car c){
c.run();
c.show();
}}
abstract class Car{
public void run(){
System.out.println("car run");
}
public void show(){
System.out.println(getClass().getName());
}}
private class Inner {
String name="inner";
void showName(){
System.out.println(name);
}
}
public static void main(String] args) {
Inner inner = new Outer().new Inner();
System.out.println(inner.name);
}
}
">2.public class Outer {public String name="Outer";
private class Inner {
String name="inner";
void showName(){
System.out.println(name);
}
}
public static void main(String] args) {
Inner inner = new Outer().new Inner();
System.out.println(inner.name);
}
}
}
}
class Rectangle extends Shape {
void display() { //实现抽象类的方法
System.out.println("Rectangle");
}
}
class Triangle extends Shape {
void display() { //实现抽象类的方法
System.out.println("Triangle");
}
}
public class AbstractClassDemo{
public static void main(String args]){
(new Circle()).display();//定义无名对象来调用对应的display方法
(new Rectangle()).display();
(new Triangle()).display();
}
}
abstract class Shape { //定义抽象类Shape和抽象方法display
abstract void display();
}
class Circle extends Shape {
void display() {//实现抽象类的方法
System.out.println("Circle");
}
}
class Rectangle extends Shape {
void display() { //实现抽象类的方法
System.out.println("Rectangle");
}
}
class Triangle extends Shape {
void display() { //实现抽象类的方法
System.out.println("Triangle");
}
}
public class AbstractClassDemo{
public static void main(String args]){
(new Circle()).display();//定义无名对象来调用对应的display方法
(new Rectangle()).display();
(new Triangle()).display();
}
}
list.add("demo_2");
list.add("demo_3");
ListIterator it = list.listIterator();
while(it.hasPrevious()) {
Object obj = it.previous();
System.out.print(obj+" ");
}
}
}
">4.代码三:import java.util.*;
public class Test03 {
public static void main(String] args) {
ArrayList list = new ArrayList();
list.add("demo_1");
list.add("demo_2");
list.add("demo_3");
ListIterator it = list.listIterator();
while(it.hasPrevious()) {
Object obj = it.previous();
System.out.print(obj+" ");
}
}
}
A、public static void methodOne(int i){ }
B、public void methodTwo(int i){ }
C、public static void methodThree(int i,intj){ }
D、public static void methodForth(inti){ }
list.add("b");
list.add("c");
for (String obj : list) {
System.out.println(obj);
}
}
}
">6.代码二:import java.util.ArrayList;
public class Test02 {
public static void main(String] args) {
ArrayList list = new ArrayList();
list.add("a");
list.add("b");
list.add("c");
for (String obj : list) {
System.out.println(obj);
}
}
}
for (int i=0;i<list.length;i++)
System.out.print(listi]+" ");
System.out.println();
}
public static void main(String] args){
int] list1={0,1,2,3};
int] list2=new intlist1.length];
list2=list1;
PrintLst("数组1",list1);
PrintLst("数组2",list2);
list12]=list12]+10;
PrintLst("修改数组1后,数组2为",list2);
}}
">7.阅读下列程序,并给出程序运行的结果。public class CopyArray{
public static void PrintLst(String s,int] list){
System.out.print(s+":");
for (int i=0;i<list.length;i++)
System.out.print(listi]+" ");
System.out.println();
}
public static void main(String] args){
int] list1={0,1,2,3};
int] list2=new intlist1.length];
list2=list1;
PrintLst("数组1",list1);
PrintLst("数组2",list2);
list12]=list12]+10;
PrintLst("修改数组1后,数组2为",list2);
}}
for (int i=0;i<list.length;i++)
System.out.print(listi]+" ");
System.out.println();
}
public static void main(String] args){
int] list1={0,1,2,3};
int] list2=new intlist1.length];
list2=list1;
PrintLst("数组1",list1);
PrintLst("数组2",list2);
list12]=list12]+10;
PrintLst("修改数组1后,数组2为",list2);
}}
">8.阅读下列程序,并给出程序运行的结果。Public class CopyArray{
public static void PrintLst(String s,int] list){
System.out.print(s+":");
for (int i=0;i<list.length;i++)
System.out.print(listi]+" ");
System.out.println();
}
public static void main(String] args){
int] list1={0,1,2,3};
int] list2=new intlist1.length];
list2=list1;
PrintLst("数组1",list1);
PrintLst("数组2",list2);
list12]=list12]+10;
PrintLst("修改数组1后,数组2为",list2);
}}
}
class Beta extends Alpha {
String getType() { return "beta"; }
}
class Gamma extends Beta {
String getType() { return "gamma"; }
public static void main(String] args) {
Alpha g1 = new Beta();
Alpha g2 = new Gamma();
System.out.println(g1.getType() + " " + g2.getType());
}
}
选项: A:alpha alpha
B:gamma gamma
C:alpha beta
D:beta gamma
">11.下面程序运行结果为( )。class Alpha {
String getType() { return "alpha"; }
}
class Beta extends Alpha {
String getType() { return "beta"; }
}
class Gamma extends Beta {
String getType() { return "gamma"; }
public static void main(String] args) {
Alpha g1 = new Beta();
Alpha g2 = new Gamma();
System.out.println(g1.getType() + " " + g2.getType());
}
}
选项: A:alpha alpha
B:gamma gamma
C:alpha beta
D:beta gamma
abstract class Takecare {
protected void speakHello() {} //1
public abstract static void cry(); //2
static int f(){ return 0 ;} //3
abstract float g(); //4
}
选项: A:1
B:2
C:3
D:4
private int i = 0; //此属性值用于检验
Leaf increment(){ //定义方法increment(),返回值是Leaf类的对象
i++;
return (1) ;//将当前对象的地址作为返回值返回
}
void print() {
System.out.println(" i = " + i);
}
public static void main(String args]){
Leaf x = (2); //创建Leaf类的对象x
x.increment().increment().increment().print();
}//多次调用方法increment(),返回的都是x的地址,i 值表示调用次数
}
输出结果为 i = (3)
try{
FileOutputStream out=new FileOutputStream(f) ;
out.write(a) ;
out.close () ;
FileInputStream in=new FileInputStream(f);byte ] tom= new byte100];
int m = in.read(tom) ;
String s=new String(tom,0, m) ;
System.out.printf("%d : %s" , m,s);
}catch (IOException e){}
}
}
">14.阅读以下程序,写出输出结果:import java.io.*;
public class E{
public static void main(String args]){
int n=-1;
File f =new File("hello.txt") ;byte ] a="abcd".getBytes () ;
try{
FileOutputStream out=new FileOutputStream(f) ;
out.write(a) ;
out.close () ;
FileInputStream in=new FileInputStream(f);byte ] tom= new byte100];
int m = in.read(tom) ;
String s=new String(tom,0, m) ;
System.out.printf("%d : %s" , m,s);
}catch (IOException e){}
}
}
}
}
">15.请说出下面中【代码】的输出结果
interface Com {
int add(int a,int b);
public static int get(int n){
return n;
}
public default int see(int n){
return n;
}
public default int look(int n){
return n;
}
}
class A implements Com{
public int add(int a,int b) {
return a+b;
}
public int see(int n){
return n+1;
}
}
public class Main {
public static void main(String args]) {
A a = new A();
int m = a.add(12,6);
int n =Com.get(12);
int t = a.see(6);
int q = a.look(6);
System.out.printf("%d:%d:%d:%d",m,n,t,q); //【代码】
}
}
abstract class A {
abstract float getFloat (); //1
void f() //2
{ }
}
public class B extends A {
private float m = 1.0f; //3
private float getFloat () //4
{ return m;
}
}
选项: A:1
B:2
C:3
D:4
} catch (java.io.IOException ex){
System.out.print("IOException!");
} catch (java.lang.Exception ex){
System.out.print("Exception!");
}
}
选项: A:IOException!
B:IOException!Exception!
C:FileNotFoundException!IOException!
D:FileNotFoundException!IOException!Exception!
">19.getCustomerInfo()方法如下,try中可以捕获三种类型的异常,如果在该方法运行中产生了一个IOException,将会输出什么结果( )。
public void getCustomerInfo() {
try {
// do something that may cause an Exception
} catch (java.io.FileNotFoundException ex){
System.out.print("FileNotFoundException!");
} catch (java.io.IOException ex){
System.out.print("IOException!");
} catch (java.lang.Exception ex){
System.out.print("Exception!");
}
}
选项: A:IOException!
B:IOException!Exception!
C:FileNotFoundException!IOException!
D:FileNotFoundException!IOException!Exception!