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单选题
Given the following code:     1) public void modify() {     2) int i, j, k;     3) i = 100;     4) while ( i > 0 ) {     5) j = i * 2;  6) System.out.println (" The value of j is " + j );     7) k = k + 1;     8) i--;     9) }  10) }  Which line might cause an error during compilation?()
A

 line 4

B

 line 6

C

 line 7

D

 line 8


参考答案

参考解析
解析: 这个问题在前面有关变量的类型及其作用域的问题中讨论过,局部变量在使用前必须显式初始化,而代码中的变量k在使用前没有。
更多 “单选题Given the following code:     1) public void modify() {     2) int i, j, k;     3) i = 100;     4) while ( i  0 ) {     5) j = i * 2;  6) System.out.println (" The value of j is " + j );     7) k = k + 1;     8) i--;     9) }  10) }  Which line might cause an error during compilation?()A  line 4B  line 6C  line 7D  line 8” 相关考题
考题 What happens when you try to compile and run the following program?class Mystery{String s;public static void main(String[] args){Mystery m=new Mystery();m.go();}void Mystery(){s=”constructor”;}void go(){System.out.println(s);}}()A.this code will not compileB.this code compliles but throws an exception at runtimeC.this code runs and “constructor” in the standard outputD.this code runs and writes “null” in the standard output

考题 Given:Which three methods, inserted individually at line 14, will correctly complete class Two?() A.int foo() { /* more code here */ }B.void foo() { /* more code here */ }C.public void foo() { /* more code here */ }D.private void foo() { /* more code here */ }E.protected void foo() { /* more code here */ }

考题 Given:Which four code fragments, inserted independently at line 7, will compile?() A.public void m1() { }B.protected void m1() { }C.private void m1() { }D.void m2() { }E.public void m2() { }F.protected void m2() { }G.private void m2() { }

考题 Given:Which method will complete this class?() A.public int compareTo(Object o){/*more code here*/}B.public int compareTo(Score other){/*more code here*/}C.public int compare(Score s1,Score s2){/*more code here*/}D.public int compare(Object o1,Object o2){/*more code here*/}

考题 Which lines of code are valid declarations of a native method when occurring within the declaration of the following class?()    public class Qf575 {   // insert declaration of a native method here   }  A、native public void setTemperature(int kelvin);B、private native void setTemperature(int kelvin);C、protected int native getTemperature();D、public abstract native void setTemperature(int kelvin);E、native int setTemperature(int kelvin) {}

考题 Which line contains a constructor in this class definition?()   public class Counter { // (1)   int current, step;   public Counter(int startValue, int stepValue) { // (2)   set(startValue);   setStepValue(stepValue);  }   public int get() { return current; } // (3)   public void set(int value) { current = value; } // (4)   public void setStepValue(int stepValue) { step = stepValue; } // (5)  }  A、Code marked with (1) is a constructorB、Code marked with (2) is a constructorC、Code marked with (3) is a constructorD、Code marked with (4) is a constructorE、Code marked with (5) is a Constructor

考题 Given the following code:     1) public void modify() {     2) int i, j, k;     3) i = 100;     4) while ( i  0 ) {     5) j = i * 2;  6) System.out.println (" The value of j is " + j );     7) k = k + 1;     8) i--;     9) }  10) }  Which line might cause an error during compilation?()   A、 line 4B、 line 6C、 line 7D、 line 8

考题 interface A { public int getValue() }  class B implements A {  public int getValue() { return 1; }  }  class C extends B {  // insert code here  }  Which three code fragments, inserted individually at line 15, make use of polymorphism?()A、 public void add(C c) { c.getValue(); }B、 public void add(B b) { b.getValue(); }C、 public void add(A a) { a.getValue(); }D、 public void add(A a, B b) { a.getValue(); }E、 public void add(C c1, C c2) { c1.getValue(); }

考题 public class Plant {  private String name;  public Plant(String name) { this.name = name; }  public String getName() { return name; }  }  public class Tree extends Plant {  public void growFruit() { }  public void dropLeaves() { }  }  Which is true?() A、 The code will compile without changes.B、 The code will compile if public Tree() { Plant(); } is added to the Tree class.C、 The code will compile if public Plant() { Tree(); } is added to the Plant class.D、 The code will compile if public Plant() { this(”fern”); } is added to the Plant class.E、 The code will compile if public Plant() { Plant(”fern”); } is added to the Plant class.

考题 Given the following code:     1) class Parent {     2) private String name;     3) public Parent(){}     4) }  5) public class Child extends Parent {     6) private String department;  7) public Child() {}  8) public String getValue(){ return name; }     9) public static void main(String arg[]) {     10) Parent p = new Parent();     11) }  12) }  Which line will cause error?()   A、 line 3B、 line 6C、 line 7D、 line 8E、 line 10

考题 Given the following code:     public class Person{     int arr[] = new int[10];  public static void main(String a[]) {     System.out.println(arr[1]);     }     }  Which statement is correct?() A、 When compilation some error will occur.B、 It is correct when compilation but will cause error when running.C、 The output is zero.D、 The output is null.

考题 Which code fragments will succeed in printing the last argument given on the command line to the standard output, and exit gracefully with no output if no arguments are given?()   CODE FRAGMENT a:   public static void main(String args[]) {   if (args.length != 0)   System.out.println(args[args.length-1]);   }   CODE FRAGMENT b:   public static void main(String args[]) {   try { System.out.println(args[args.length]); }   catch (ArrayIndexOutOfBoundsException e) {}   }   CODE FRAGMENT c:   public static void main(String args[]) {   int ix = args.length;   String last = args[ix];   if (ix != 0) System.out.println(last);   }   CODE FRAGMENT d:   public static void main(String args[]) {   int ix = args.length-1;   if (ix  0) System.out.println(args[ix]);   }   CODE FRAGMENT e:   public static void main(String args[]) {   try { System.out.println(args[args.length-1]);  }catch (NullPointerException e) {}   }  A、Code fragment a.B、Code fragment b.C、Code fragment c.D、Code fragment d.E、Code fragment e.

考题 Given the following code:    public class Test {  void printValue(int m){  do {  System.out.println("The value is"+m);     }  while( --m  10 )     }  public static void main(String arg[]) {     int i=10;  Test t= new Test();     t.printValue(i);     }     }  Which will be output?()    A、 The value is 8B、 The value is 9C、 The value is 10D、 The value is 11

考题 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( )?A、 The program runs and prints nothing.B、 The program runs and prints “Finally”.C、 The code comiles. But an exception is thrown at runtime.D、 The code will not compile because the catch block is missing.

考题 Given that a static method doIt() in a class Work represents work to be done, what block of code will succeed in starting a new thread that will do the work?   CODE BLOCK a:   Runnable r = new Runnable() {   public void run() {   Work.doIt();   }   };   Thread t = new Thread(r);   t.start();   CODE BLOCK b:   Thread t = new Thread() {  public void start() {   Work.doIt();  }  };   t.start();   CODE BLOCK c:   Runnable r = new Runnable() {   public void run() {   Work.doIt();   }   };   r.start();  CODE BLOCK d:   Thread t = new Thread(new Work());   t.start();   CODE BLOCK e:   Runnable t = new Runnable() {   public void run() {   Work.doIt();   }   };   t.run();  A、Code block a.B、Code block B.C、Code block c.D、Code block d.E、Code block e.

考题 Given:   10. class One {   11. void foo() { }   12. }   13. class Two extends One {   14. //insert method here   15. }   Which three methods, inserted individually at line 14, will correctly complete class Two?()A、 public void foo() { /* more code here */ }B、 private void foo() { /* more code here */ }C、 protected void foo() { /* more code here */ }D、 int foo() { /* more code here */ }  E、 void foo() { /* more code here */ }

考题 You use the following declaration to add a Web user control named TestUserControl.ascx to an ASP.NET page named TestPage.aspx.    You add the following code to the code-behind file of TestPage.aspx.  private void TestMethod(){ ...}You define the following delegate.  public delegate void MyEventHandler();  You need to add an event of type MyEventHandler named MyEvent to TestUserControl.ascx and attach the page’s TestMethod method to the event. Which two actions should you perform?()A、Add the following line of code to TestUserControl.ascx.cs. public event MyEventHandler MyEvent;B、Add the following line of code to TestUserControl.ascx.cs. public MyEventHandler MyEvent;C、Replace the TestUserControl.ascx reference in TestPage.aspx with the following declaration. uc:TestUserControl ID="testControl" runat="server" OnMyEvent="TestMethod"/D、Replace the TestUserControl.ascx reference in TestPage.aspx with the following declaration. uc:TestUserControl ID="testControl" runat="server" MyEvent="TestMethod"/

考题 单选题Which code fragments will succeed in printing the last argument given on the command line to the standard output, and exit gracefully with no output if no arguments are given?()   CODE FRAGMENT a:   public static void main(String args[]) {   if (args.length != 0)   System.out.println(args[args.length-1]);   }   CODE FRAGMENT b:   public static void main(String args[]) {   try { System.out.println(args[args.length]); }   catch (ArrayIndexOutOfBoundsException e) {}   }   CODE FRAGMENT c:   public static void main(String args[]) {   int ix = args.length;   String last = args[ix];   if (ix != 0) System.out.println(last);   }   CODE FRAGMENT d:   public static void main(String args[]) {   int ix = args.length-1;   if (ix  0) System.out.println(args[ix]);   }   CODE FRAGMENT e:   public static void main(String args[]) {   try { System.out.println(args[args.length-1]);  }catch (NullPointerException e) {}   }A Code fragment a.B Code fragment b.C Code fragment c.D Code fragment d.E Code fragment e.

考题 多选题Given the following class, which statements can be inserted at position 1 without causing the code to fail compilation?()   public class Q6db8 {   int a;   int b = 0;   static int c;   public void m() {   int d;   int e = 0;   // Position 1   }   }Aa++;Bb++;Cc++;Dd++;Ee++;

考题 单选题Given the following code:     public class Person{ static int arr[] = new int[10];  public static void main(String a[]) {     System.out.println(arr[1];)     }     }  Which statement is correct?()A  When compilation some error will occur.B  It is correct when compilation but will cause error when running.C  The output is zero.D  The output is null.

考题 填空题Given the following code, write a line of code that, when inserted at the indicated location, will make the overriding method in Extension invoke the overridden method in class Base on the current object.   class Base {   public void print( ) {   System.out.println("base");   }   }   class Extention extends Base {   public void print( ) {   System.out.println("extension");   // insert line of implementation here   }   }   public class Q294d {   public static void main(String args[]) {   Extention ext = new Extention( );   ext.print( );   }   }   Fill in a single line of implementation.()

考题 多选题Given the following code, which code fragments, when inserted at the indicated location, will succeed in making the program display a button spanning the whole window area?()   import java.awt.*;   public class Q1e65 {   public static void main(String args[]) {   Window win = new Frame();   Button but = new Button("button");   // insert code fragment here  win.setSize(200, 200);   win.setVisible(true);   }   }Awin.setLayout(new BorderLayout()); win.add(but);Bwin.setLayout(new GridLayout(1, 1)); win.add(but);Cwin.setLayout(new BorderLayout()); win.add(but, BorderLayout.CENTER);Dwin.add(but);Ewin.setLayout(new FlowLayout()); win.add(but);

考题 单选题Given that a static method doIt() in a class Work represents work to be done, what block of code will succeed in starting a new thread that will do the work?   CODE BLOCK a:   Runnable r = new Runnable() {   public void run() {   Work.doIt();   }   };   Thread t = new Thread(r);   t.start();   CODE BLOCK b:   Thread t = new Thread() {  public void start() {   Work.doIt();  }  };   t.start();   CODE BLOCK c:   Runnable r = new Runnable() {   public void run() {   Work.doIt();   }   };   r.start();  CODE BLOCK d:   Thread t = new Thread(new Work());   t.start();   CODE BLOCK e:   Runnable t = new Runnable() {   public void run() {   Work.doIt();   }   };   t.run();A Code block a.B Code block B.C Code block c.D Code block d.E Code block e.

考题 单选题Given the following code:     1) class Parent {     2) private String name;     3) public Parent(){}     4) }  5) public class Child extends Parent {     6) private String department;  7) public Child() {}  8) public String getValue(){ return name; }     9) public static void main(String arg[]) {     10) Parent p = new Parent();     11) }  12) }  Which line will cause error?()A  line 3B  line 6C  line 7D  line 8E  line 10

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 单选题Given the following code:     public class Person{     int arr[] = new int[10];  public static void main(String a[]) {     System.out.println(arr[1]);     }     }  Which statement is correct?()A  When compilation some error will occur.B  It is correct when compilation but will cause error when running.C  The output is zero.D  The output is null.

考题 单选题Given the following code:    public class Test {  void printValue(int m){  do {  System.out.println("The value is"+m);     }  while( --m  10 )     }  public static void main(String arg[]) {     int i=10;  Test t= new Test();     t.printValue(i);     }     }  Which will be output?()A  The value is 8B  The value is 9C  The value is 10D  The value is 11