现有:
public interface A {}
以下哪项声明是合法的?()
11.classa {
12. public void process() { System.out.print(”a,”); } }
13. class b extends a {
14. public void process() throws IOException {
15. super.process();
16. System.out.print(”b,”);
17. throw new IOException();
18. } }
19. public static void main(String[] args) {
20. try { new b().process(); }
21. catch (IOException e) { System.out.println(”Exception”); } }
What is the result?()
Class TestException
1. public class TestException extends Exception {
2. } Class a:
1. public class a {
2.
3. public String sayHello(String name) throws TestException {
4.
5. if(name == null) {
6. throw new TestException();
7. }
8.
9. return “Hello “+ name;
10. }
11.
12. }
A programmer wants to use this code in an application:
45. A a=new A();
46. System.out.println(a.sayHello(”John”));
Which two are true?()
在J2EE中,有如下代码在Servlet1.Java中
Import javax.servlet.*;
Import javax.servlet.http.*
Import java.io.IOException;
Import java.io.PrintWriter;
Public class Servlet1 extends HttpServlet{
Public void init () throw ServletException {}
Public void service(HttpServletRequest request,
HttpServletResponce response) throws ServletException,IOException{
PrintWriter out=response.getWriter();
Out.println(“hello!”); } }
假如编译Servlet要具备的环境都已经建立好。现在用完全正确的命令编译该文件,对于以下成熟正确的是()
现有:
interface Data {public void load();}
abstract class Info {public abstract void load();}
下列类定义中正确使用Data和Info的是哪项?()
int [] my_Array;
my_Array = new int[5];
for(int count = 0; count <= 5; count++)
System.out.println(my_Array[count]);
结果是()
int [] my_Array;
my_Array = new int[5];
for(int count = 0; count <= 5; count++)
System.out.println(my_Array[count]);
以上Java代码运行的结果是()。
class java {
public static void main(String [] java) {
for (int Java = 1; Java 〈 java.length; Java++)
System.out.print("java ");
}
}
和命令行:
java java java java java
结果为:()
import java.io.*;
public class Forest implements Serializable {
private Tree tree = new Tree();
public static void main(String [] args) {
Forest f= new Forest();
try {
FileOutputStream fs = new FileOutputStream(”Forest.ser”);
ObjectOutputStream os = new ObjectOutputStream(fs);
os.writeObject(f); os.close();
} catch (Exception ex) { ex.printStackTrace(); }
}
}
class Tree { }
What is the result?()
为将数组myArray的长度由6改为10,现采取以下编码:
int[] myArray = new int[6];
myArray = new int[10];
代码执行后,以下叙述哪项是正确的?()
为将数组myArray的长度由3改为6,现采取以下编码:
int[]myArray=new int [3];
myArray=new int[6];
代码执行后,以下叙述哪项是正确的?()
public class TestOne {
public static void main (String[] args) throws Exception {
Thread.sleep(3000);
System.out.println(”sleep”);
}
}
What is the result?()
public class A extends Thread {
A() {
setDaemon(true);
}
public void run() {
(new B()).start();
try {
Thread.sleep(60000);
} catch (InterruptedException x) {}
System.out.println(“A done”);
}
class B extends Thread {
public void run() {
try {
Thread.sleep(60000);
} catch (InterruptedException x) {}
System.out.println(“B done”);
}
}
public static void main(String[] args) {
(new A()).start();
}
}
What is the result?()
Given:
11. public void genNumbers() {
12. ArrayList numbers = new ArrayList();
13. for (int i=0; i<10; i++) {
14. int value = i * ((int) Math.random());
15. Integer intObj = new Integer(value);
16. numbers.add(intObj);
17. }
18. System.out.println(numbers);
19. }
Which line of code marks the earliest point that an object referenced by intObj becomes a candidate for garbage collection?()
11. public void genNumbers() {
12. ArrayList numbers = new ArrayList();
13. for (int i=0; i<10; i++) {
14. int value = i * ((int) Math.random());
15. Integer intObj = new Integer(value);
16. numbers.add(intObj);
17. }
18. System.out.println(numbers);
19. }
Which line of code marks the earliest point that an object referenced by intObj becomes a candidate for garbage collection?()
给出下列java源代码:
//Point x
Public class Interesting{}
在源代码//point x处添加()能符合java语法
阅读以下代码:
public class Test{
public static void main(){
System.out.println(“x=”+x); } }
请问,代码运行的结果是?()
public class Car {
private int wheelCount;
private String vin;
public Car(String vin) {
this.vin = vin;
this.wheelCount = 4;
}
public String drive() {
return “zoom-zoom”;
}
public String getInfo() {
return “VIN: “+ vin + “wheels: “+ wheelCount;
}
}
And:
public class MeGo extends Car {
public MeGo(String vin) {
this.wheelCount = 3;
}
}
What two must the programmer do to correct the compilation errors?()
1. class Pizza {
2. java.util.ArrayList toppings;
3. public final void addTopping(String topping) {
4. toppings.add(topping);
5. }
6. }
7. public class PepperoniPizza extends Pizza {
8. public void addTopping(String topping) {
9. System.out.println(”Cannot add Toppings”);
10. }
11. public static void main(String[] args) {
12. Pizza pizza = new PepperoniPizza();
13. pizza.addTopping(”Mushrooms”);
14. }
15. }
What is the result?()
public class X {
public static void main (String[]args) {
string s = new string (“Hello”);
modify(s);
System.out.printIn(s);
}
public static void modify (String s) {
s += “world!”;
}
}
What is the result?()
分析下列Java代码:
class A {
public static void main(String[] args) {
method(); }
static void method() { try {
System.out.println("Hello"); System.exit(0); }
finally {
System.out.println("good-bye"); } } }
编译运行后,输出结果是()。
Assuming that the serializeBanana2() and the deserializeBanana2() methods will correctly use Java serialization and given:
import java.io.*;
class Food {Food() { System.out.print(”1”); } }
class Fruit extends Food implements Serializable {
Fruit() { System.out.print(”2”); } }
public class Banana2 extends Fruit { int size = 42;
public static void main(String [] args) {
Banana2 b = new Banana2();
b.serializeBanana2(b); // assume correct serialization
b = b.deserializeBanana2(b); // assume correct
System.out.println(” restored “+ b.size + “ “); }
// more Banana2 methods
}
What is the result?()
import java.util.*;
public class PQ {
public static void main(String[] args) {
PriorityQueue
pq.add(”carrot”);
pq.add(”apple”);
pq.add(”banana”);
System.out.println(pq.poll() +”:” + pq.peek());
}
}
What is the result?()
1. public class SimpleCalc {
2. public int value;
3. public void calculate() { value += 7; }
4. }
And:
1. public class MultiCalc extends SimpleCalc {
2. public void calculate() { value -= 3; }
3. public void calculate(int multiplier) {
4. calculate();
5. super.calculate();
6. value *=multiplier;
7. }
8. public static void main(String[] args) {
9. MultiCalc calculator = new MultiCalc();
10. calculator.calculate(2);
11. System.out.println(”Value is: “+ calculator.value);
12. }
13. }
What is the result?()
现有:
public interface A {}
以下哪项声明是合法的?()
现有:
public interface A {}
以下哪项声明是合法的?()
What is wrong with the following code?()
class MyException extends Exception {}
public class Qb4ab {
public void foo() { try { bar(); } finally { baz();
} catch (MyException e) {}
}
public void bar() throws MyException {
throw new MyException();
}
public void baz() throws RuntimeException {
throw new RuntimeException();
}
}
public class X {
public static void main(String [] args) {
try {
badMethod();
System.out.print(“A”);
}
catch (RuntimeException ex) {
System.out.print(“B”);
}
catch (Exception ex1) {
System.out.print(“C”);
}
finally {
System.out.print(“D”);
}
System.out.print(“E”);
}
public static void badMethod() {
throw new RuntimeException();
}
}
What is the result?()
public class Test {
public static void aMethod() throws Exception {
try {
throw new Exception();
} finally {
System.out.println(“finally”);
}
}
public static void main(String args[]) {
try {
aMethod();
} catch (Exception e) {
System.out.println(“exception”);
}
System.out.println(“finished”);
}
}
What is the result?()
public class Threads2 implements Runnable {
public void nun() {
System.out.println(”run.”);
throw new RuntimeException(”Problem”);
}
public static void main(String[] args) {
Thread t = new Thread(new Threads2());
t.start();
System.out.println(”End of method.”);
}
}
Which two can be results?()
import java.io.IOException;
public class ExceptionTest(
public static void main (Stringargs)
try (
methodA();
) catch (IOException e) (
system.out.printIn(“Caught IOException”);
) catch (Exception e) (
system.out.printIn(“Caught Exception”);
)
)
public void methodA () {
throw new IOException ();
}
What is the result?()
现有:
class ThreadExcept implements Runnable {
public void run() { throw new RuntimeException("exception "); }
public static void main(String [] args) {
new Thread(new ThreadExcept()).start();
try {
int x = Integer.parseInt(args[0]);
Thread.sleep(x);
System.out.print("main ");
} catch (Exception e) { }
}
}
和命令行:
java ThreadExcept 1000
哪一个是结果?()
现有:
class ThreadExcept implements Runnable {
public void run() { throw new RuntimeException("exception "); }
public static void main(Stri_ng [] args) {
new Thread (new ThreadExcept()).start();
try {
int x=Integer.parselnt (args [0]);
Thread. sleep (x);
System.out.print("main");
} catch (Exception e) { }
}
}
和命令行: java ThreadExcept l000
哪一个是结果?()
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