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单选题
1. public class A { 2. 3. private int counter = 0; 4. 5. public static int getInstanceCount() { 6. return counter; 7. } 8. 9. public A() { 10. counter++; 11. } 12. 13. } Given this code from Class B: 25.A a1 =new A(); 26. A a2 =new A(); 27. A a3 =new A(); 28. System.out.printIn(A.getInstanceCount() ); What is the result?()
A
Compilation of class A fails.
B
Line 28 prints the value 3 to System.out.
C
Line 28 prints the value 1 to System.out.
D
A runtime error occurs when line 25 executes.
E
Compilation fails because of an error on line 28.
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更多 “单选题1. public class A { 2. 3. private int counter = 0; 4. 5. public static int getInstanceCount() { 6. return counter; 7. } 8. 9. public A() { 10. counter++; 11. } 12. 13. } Given this code from Class B: 25.A a1 =new A(); 26. A a2 =new A(); 27. A a3 =new A(); 28. System.out.printIn(A.getInstanceCount() ); What is the result?()A Compilation of class A fails.B Line 28 prints the value 3 to System.out.C Line 28 prints the value 1 to System.out.D A runtime error occurs when line 25 executes.E Compilation fails because of an error on line 28.” 相关考题
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考题
ClassOne.java: 1. package com.abe.pkg1; 2. public class ClassOne { 3. private char var = ‘a’; 4. char getVar() { return var; } 5. } ClassTest.java: 1. package com.abe.pkg2; 2. import com.abc.pkg1.ClassOne; 3. public class ClassTest extends ClassOne { 4. public static void main(String[] args) { 5. char a = new ClassOne().getVar();6. char b = new ClassTest().getVar(); 7. } 8. } What is the result?()A、 Compilation fails.B、 Compilation succeeds and no exceptions are thrown.C、 An exception is thrown at line 5 in ClassTest.java.D、 An exception is thrown at line 6 in ClassTest.java.
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考题
1. public class OuterClass { 2. private double d1 = 1.0; 3. // insert code here 4. } Which two are valid if inserted at line 3?() A、 static class InnerOne { public double methoda() { return d1; } }B、 static class InnerOne { static double methoda() { return d1; } }C、 private class InnerOne { public double methoda() { return d1; } }D、 protected class InnerOne { static double methoda() { return d1; } }E、 public abstract class InnerOne { public abstract double methoda(); }
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1. public class Test { 2. int x= 12; 3. public void method(int x) { 4. x+=x; 5. System.out.println(x); 6. } 7. } Given: 34. Test t = new Test(); 35. t.method(5); What is the output from line 5 of the Test class?() A、 5B、 10C、 12D、 17E、 24
考题
1. public class test ( 2. public static void main(string args[]) { 3. int 1= 0; 4. while (i) { 5. if (i==4) { 6. break; 7. } 8. ++i; 9. } 10. 11. } 12. ) What is the value of i at line 10?()A、 0B、 3C、 4D、 5E、 The code will not compile.
考题
1. public class A { 2. 3. private int counter = 0; 4. 5. public static int getInstanceCount() { 6. return counter; 7. } 8. 9. public A() { 10. counter++; 11. } 12. 13. } Given this code from Class B: 25.A a1 =new A(); 26. A a2 =new A(); 27. A a3 =new A(); 28. System.out.printIn(A.getInstanceCount() ); What is the result?() A、 Compilation of class A fails.B、 Line 28 prints the value 3 to System.out.C、 Line 28 prints the value 1 to System.out.D、 A runtime error occurs when line 25 executes.E、 Compilation fails because of an error on line 28.
考题
1. public class Blip { 2. protected int blipvert(int x) { return 0; } 3. } 4. class Vert extends Blip { 5. // insert code here 6. } Which five methods, inserted independently at line 5, will compile?() A、 public int blipvert(int x) { return 0; }B、 private int blipvert(int x) { return 0; }C、 private int blipvert(long x) { return 0; }D、 protected long blipvert(int x, int y) { return 0; }E、 protected int blipvert(long x) { return 0; }F、 protected long blipvert(long x) { return 0; }G、protected long blipvert(int x) { return 0; }
考题
单选题1. public class A { 2. public void doit() { 3. } 4. public String doit() { 5. return “a”; 6. } 7. public double doit(int x) { 8. return 1.0; 9. } 10.} What is the result?()A
An exception is thrown at runtime.B
Compilation fails because of an error in line 7.C
Compilation fails because of an error in line 4.D
Compilation succeeds and no runtime errors with class A occur.
考题
单选题1. public class Test { 2. int x= 12; 3. public void method(int x) { 4. x+=x; 5. System.out.println(x); 6. } 7. } Given: 34. Test t = new Test(); 35. t.method(5); What is the output from line 5 of the Test class?()A
5B
10C
12D
17E
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考题
单选题1. public class A { 2. 3. private int counter = 0; 4. 5. public static int getInstanceCount() { 6. return counter; 7. } 8. 9. public A() { 10. counter++; 11. } 12. 13. } Given this code from Class B: 25.A a1 =new A(); 26. A a2 =new A(); 27. A a3 =new A(); 28. System.out.printIn(A.getInstanceCount() ); What is the result?()A
Compilation of class A fails.B
Line 28 prints the value 3 to System.out.C
Line 28 prints the value 1 to System.out.D
A runtime error occurs when line 25 executes.E
Compilation fails because of an error on line 28.
考题
单选题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?()A
process(bytes);B
BitUtils.process(bytes);C
app.BitUtils.process(bytes);D
util.BitUtils.process(bytes);E
import util.BitUtils. *; process(bytes);F
SomeApp cannot use the process method in BitUtils.
考题
单选题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?()A
Value is: 8B
Compilation fails.C
Value is: 12D
Value is: -12E
The code runs with no output.F
An exception is thrown at runtime.
考题
多选题Given: 1. public class ConstOver { 2. public constOver(int x, int y, int z) { 3. } 4. } Which two overload the ConstOver Constructor?()AConstOver() {}Bprotected int ConstOver(){}Cprivate ConstOver(int z, int y, byte x ) {}Dpublic Object ConstOver(Int x, int y, int z) {}Epubic void ConstOver (byte x, byte y, byte z) {}
考题
单选题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?()A
0B
1C
2D
3
考题
单选题1. public class X { 2. public static void main (String[]args) { 3. int [] a = new int [1] 4. modify(a); 5. System.out.printIn(a[0]); 6. } 7. 8. public static void modify (int[] a) { 9. a[0] ++; 10. } 11. } What is the result?()A
The program runs and prints “0”B
The program runs and prints “1”C
The program runs but aborts with an exception.D
An error “possible undefined variable” at line 4 causes compilation to fail.E
An error “possible undefined variable” at line 9 causes compilation to fail.
考题
单选题1. public class test ( 2. public static void main(string args[]) { 3. int 1= 0; 4. while (i) { 5. if (i==4) { 6. break; 7. } 8. ++i; 9. } 10. 11. } 12. ) What is the value of i at line 10?()A
0B
3C
4D
5E
The code will not compile.
考题
多选题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?()AThe application will crash.BThe code on line 29 will be executed.CThe code on line 5 of class A will execute.DThe code on line 5 of class B will execute.EThe exception will be propagated back to line 27.
考题
多选题1. class Super { 2. private int a; 3. protected Super(int a) { this.a = a; } 4. } ..... 11. class Sub extends Super { 12. public Sub(int a) { super(a); } 13. public Sub() { this.a= 5; } 14. } Which two, independently, will allow Sub to compile?()AChange line 2 to: public int a;BChange line 2 to: protected int a;CChange line 13 to: public Sub() { this(5); }DChange line 13 to: public Sub() { super(5); }EChange line 13 to: public Sub() { super(a); }
考题
多选题1. public class Blip { 2. protected int blipvert(int x) { return 0; } 3. } 4. class Vert extends Blip { 5. // insert code here 6. } Which five methods, inserted independently at line 5, will compile?()Apublic int blipvert(int x) { return 0; }Bprivate int blipvert(int x) { return 0; }Cprivate int blipvert(long x) { return 0; }Dprotected long blipvert(int x, int y) { return 0; }Eprotected int blipvert(long x) { return 0; }Fprotected long blipvert(long x) { return 0; }Gprotected long blipvert(int x) { return 0; }
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