Given a class Repetition: 1. package utils; 2. 3. public class Repetition { 4. public static String twice(String s) { return s + s; } 5. } and given another class Demo: 1. // insert code here 2. 3. public class Demo { 4. public static void main(String[] args) { 5. System.out.println(twice(”pizza”)); 6. } 7. } Which code should be inserted at line 1 of Demo.java to compile and run Demo to print“pizzapizza”?()
第1题:
1. public interface A { 2. public void doSomething(String thing); 3. } 1. public class AImpl implements A { 2. public void doSomething(String msg) { } 3. } 1. public class B { 2. public A doit() { 3. // more code here 4. } 5. 6. public String execute() { 7. // more code here 8. } 9. } 1. public class C extends B { 2. public AImpl doit() { 3. // more code here 4. } 5. 6. public Object execute() { 7. // more code here 8. } 9. } Which statement is true about the classes and interfaces in the exhibit?()
第2题:
1. public class A { 2. void A() { 3. System.out.println(“Class A”); 4. } 5. public static void main(String[] args) { 6. new A(); 7. } 8. } What is the result?()
第3题:
现有2 个文件: 1. package x; 2. public class X { 3. public static void doX() { System.out.print("doX "); } 4. } 和: 1. class Find { 2. public static void main(String [] args) { 3. //insert code here 4. } 5. } 哪两行分别插入到类Find 的第3 行将编译并产生输出“doX”? ()
第4题:
现有: 1. abstract class Color2 { 2. //insert code here 3. } 4. 5. public class Blue2 extends Color2 { 6.public String getRGB() { return "blue"; } 7. } 和4个声明: public abstract String getRGB(); abstract String getRGB(); private abstract String getRGB(); protected abstract String getRGB(); 分别插入到第2行,有多少行可以编译?()
第5题:
1. public class OuterClass { 2. private double d1 = 1.0; 3. // insert code here 4. } Which two are valid if inserted at line 3?()
第6题:
Given classes defined in two different files: 1. package util; 2. public class BitUtils { 3. public static void process(byte[]) { /* more code here */ } 4. } 1. package app; 2. public class SomeApp { 3. public static void main(String[] args) { 4. byte[] bytes = new byte[256]; 5. // insert code here 6. } 7. } What is required at line 5 in class SomeApp to use the process method of BitUtils?()
第7题:
Given 1. public class Foo { 2. public static void main (String [] args) } 3. try { return;} 4. finally { Syste.out.printIn (“Finally”);} 5. } 6. } What is the result( )?
第8题:
定义类: package utils; public class Rep{ public static String twice (String s){return s+s ;} } 再定义另一个类Demo: //insert code here public class Demo{ public static void main (String[] args){ System. out .println( twice( "Hello")); } } 在第一行插入哪项代码,可以使程序正常编译和执行?()
第9题:
static class InnerOne { public double methoda() { return d1; } }
static class InnerOne { static double methoda() { return d1; } }
private class InnerOne { public double methoda() { return d1; } }
protected class InnerOne { static double methoda() { return d1; } }
public abstract class InnerOne { public abstract double methoda(); }
第10题:
3
12
111
编译失败
第11题:
The program runs and prints nothing.
The program runs and prints “Finally”.
The code comiles. But an exception is thrown at runtime.
The code will not compile because the catch block is missing.
第12题:
import utils.*;
static import utils.*;
importutils.Repetition.*;
static importutils.Repetition.*;
import utils.Repetition.twice();
import static utils.Repetition.twice;
static import utils.Repetition.twice;
第13题:
1. public class a { 2. public void method1() { 3. try { 4. B b=new b(); 5. b.method2(); 6. // more code here 7. } catch (TestException te) { 8. throw new RuntimeException(te); 9. } 10. } 11. } 1. public class b { 2. public void method2() throws TestException { 3. // more code here 4. } 5. } 1. public class TestException extends Exception { 2. } Given: 31. public void method() { 32. A a=new a(); 33. a.method1(); 34. } Which is true if a TestException is thrown on line 3 of class b?()
第14题:
class Mineral { static String shiny() { return "1"; } } class Granite extends Mineral { public static void main(String [] args) { String s = shiny() + getShiny(); s = s + super.shiny(); System.out.println(s); } static String getShiny() { return shiny(); } } 结果为:()
第15题:
1. public class A { 2. public void method1() { 3. B b=new B(); 4. b.method2(); 5. // more code here 6. } 7. } 1. public class B { 2. public void method2() { 3.C c=new C(); 4. c.method3(); 5. // more code here 6. } 7. } 1. public class C { 2. public void method3() { 3. // more code here 4. } 5. } Given: 25. try { 26. A a=new A(); 27. a.method1(); 28. } catch (Exception e) { 29. System.out.print(”an error occurred”); 30. } Which two are true if a NullPointerException is thrown on line 3 of class C?()
第16题:
Given a class Repetition: 1.package utils; 2. 3.public class Repetition{ 4.public static String twice(Strings){returns+s;} 5.} and given another class Demo: 1.//insert code here2. 3.public class Demo{ 4.public static void main(String[]args){ 5.System.out.println(twice("pizza")); 6.} 7.} Which code should be inserted at line 1 of Demo.java to compile and run Demo to print“pizzapizza”?()
第17题:
Given classes defined in two different files: 1. package util; 2. public class BitUtils { 3. private static void process(byte[] b) { } 4. } 1. package app; 2. public class SomeApp { 3. public static void main(String[] args) { 4. byte[] bytes = new byte[256]; 5. // insert code here 6. } 7. } What is required at line 5 in class SomeApp to use the process method of BitUtils?()
第18题:
1. public class enclosingone ( 2. public class insideone{} 3. ) 4. public class inertest( 5. public static void main (string[]args)( 6. enclosingone eo= new enclosingone (); 7. //insert code here 8. ) 9. ) Which statement at line 7 constructs an instance of the inner class?()
第19题:
1. import java.util.*; 2. public class Test { 3. public static void main(String[] args) { 4. List
第20题:
process(bytes);
BitUtils.process(bytes);
app.BitUtils.process(bytes);
util.BitUtils.process(bytes);
import util.BitUtils. *; process(bytes);
SomeApp cannot use the process method in BitUtils.
第21题:
import utils.*;
import utils.Rep.*;
import static utils.Rep.twice;
static import utils.Rep.twice;
第22题:
InsideOnew ei= eo.new InsideOn();
Eo.InsideOne ei = eo.new InsideOne();
InsideOne ei = EnclosingOne.new InsideOne();
EnclosingOne.InsideOne ei = eo.new InsideOne();
第23题:
Class A
Compilation fails.
An exception is thrown at line 2.
An exception is thrown at line 6.
The code executes with no output.