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单选题
1. class super {  2. public float getNum() {return 3.0f;}  3. }  4.    5. public class Sub extends Super { 6.   7. }   Which method, placed at line 6, will cause a compiler error?()
A

  Public float getNum()   {return 4.0f; }

B

  Public void getNum ()  { }

C

  Public void getNum (double d)   { }

D

  Public double getNum (float d) {retrun 4.0f; }


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更多 “单选题1. class super {  2. public float getNum() {return 3.0f;}  3. }  4.    5. public class Sub extends Super { 6.   7. }   Which method, placed at line 6, will cause a compiler error?()A   Public float getNum()   {return 4.0f; }B   Public void getNum ()  { }C   Public void getNum (double d)   { }D   Public double getNum (float d) {retrun 4.0f; }” 相关考题
考题 1. class BaseClass {  2. private float x = 1.of;  3. protected float getVar() { return x; }  4. }  5. class SubClass extends BaseClass {  6. private float x = 2.Of;  7. // insert code here 8. }   Which two are valid examples of method overriding when inserted at line 7?() A、 float getVar() { return x; }B、 public float getVar() { return x; }C、 public double getVar() { return x; }D、 protected float getVar() { return x; }E、 public float getVar(float f) { return f; }

考题 1. class Super {  2. public float getNum() { return 3.0f; }  3. }  4.   5. public class Sub extends Super {  6.   7. }  Which method, placed at line6, causes compilation to fail?()  A、 public void getNum(){}B、 public void getNum(double d){}C、 public float getNum() { return 4.0f; }D、 public double getNum(float d) { return 4.0d; }

考题 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?() A、 Compilation will succeed for all classes and interfaces.B、 Compilation of class C will fail because of an error in line 2.C、 Compilation of class C will fail because of an error in line 6.D、 Compilation of class AImpl will fail because of an error in line 2.

考题 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?()A、 Line 33 must be called within a try block.B、 The exception thrown by method1 in class a is not required to be caught.C、 The method declared on line 31 must be declared to throw a RuntimeException.D、 On line 5 of class a, the call to method2 of class b does not need to be placed in a try/catch block.

考题 class Super {  public int getLenght( ) { return 4; }  }  public class Sub extends Super {  public long getLenght( ) { return 5; }  public static void main(String[] args) {  Super sooper = new Super( );  Sub sub = new Sub( );  System.out.println(  sooper.getLenght( ) + “,” + sub.getLenght( ) );  }  } What is the output?()A、 Just after line 13.B、 Just after line 14.C、 Just after line 15.D、 Just after line 16 (that is, as the method returns).

考题 class super {   public float getNum() {return 3.0f;}   }   public class Sub extends Super {   }   Which method, placed at line 6, will cause a compiler error?()A、 Public float getNum() {return 4.0f; }B、 Public void getNum (){}C、 Public void getNum (double d){}D、 Public double getNum (float d) {retrun 4.0f; }

考题 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 1. abstract class AbstractIt {  2. abstract float getFloat();  3. }  4. public class AbstractTest extends AbstractIt {  5. private float f1 = 1.0f;  6. private float getFloat() { return f1; }  7. }  What is the result?() A、 Compilation succeeds.B、 An exception is thrown.C、 Compilation fails because of an error at line 2.D、 Compilation fails because of an error at line 6.

考题 Given:  1. public class Method Over {  2. public void set Var (int a, int b, float c) {  3. }  4. }   Which two overload the set Var method()?A、 private void set Var(int a, float c, int b) {}B、 protected void set Var(int a, int b, float c) {}C、 public int set Var(int a, float c, int b) {return a:}D、 public int set Var(int a, int b, float c) {return a:}E、 protected float set Var(int a, int b, float c) {return c:}

考题 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?()A、 Change line 2 to: public int a;B、 Change line 2 to: protected int a;C、 Change line 13 to: public Sub() { this(5); }D、 Change line 13 to: public Sub() { super(5); }E、 Change line 13 to: public Sub() { super(a); }

考题 1. class SuperClass {  2. public a geta() {  3. return new a();  4. }  5. }  6. class SubClass extends SuperClass {  7. public b geta() {  8. return new b();  9. }  10. }  Which is true?() A、 Compilation will succeed if a extends b.B、 Compilation will succeed if b extends a.C、 Compilation will always fail because of an error in line 7.D、 Compilation will always fail because of an error in line 8.

考题 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?()A、 The application will crash.B、 The code on line 29 will be executed.C、 The code on line 5 of class A will execute.D、 The code on line 5 of class B will execute.E、 The exception will be propagated back to line 27.

考题 1. class A {  2. public String toString ()  {  3. return “4”;  4. }  5. }  6. class B extends A {  7. public String toString ()   {  8. return super.toString()  + “3”;  9. }  10. }  11. public class Test {  12.   public static void main(String[]args)  {  13.      System.out.printIn(new B());  14.      }  15. }    What is the result?()  A、 Compilation succeeds and 4 is printed.B、 Compilation succeeds and 43 is printed.C、 An error on line 9 causes compilation to fail.D、 An error on line 14 causes compilation to fail.E、 Compilation succeeds but an exception is thrown at line 9.

考题 1. class super {  2. public float getNum() {return 3.0f;}  3. }  4.    5. public class Sub extends Super { 6.   7. }   Which method, placed at line 6, will cause a compiler error?()  A、  Public float getNum()   {return 4.0f; }B、  Public void getNum ()  { }C、  Public void getNum (double d)   { }D、  Public double getNum (float d) {retrun 4.0f; }

考题 1. class A {  3. public String to String() {  4. return “4”;  5. }  6. }  7. class B extends A {  8. public String toString() { 9. return super.toString() + “3”;  10. }  11. }  12. public class Test {  13. public static void main (String[] args) {  14. System.out.printIn(new B()); 15. }  16. }   What is the result( )?   A、 Compilation succeeds and 4 is printed.B、 Compilation …………… is printed.C、 An error on line 9 cause compilation to fail.D、 An error on line 14 cause compilation to fail.E、 Compilation succeeds but an exception is thrown at line 9.

考题 单选题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?()A  Compilation will succeed for all classes and interfaces.B  Compilation of class C will fail because of an error in line 2.C  Compilation of class C will fail because of an error in line 6.D  Compilation of class AImpl will fail because of an error in line 2.

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 单选题1. class SuperClass {  2. public a geta() {  3. return new a();  4. }  5. }  6. class SubClass extends SuperClass {  7. public b geta() {  8. return new b();  9. }  10. }  Which is true?()A  Compilation will succeed if a extends b.B  Compilation will succeed if b extends a.C  Compilation will always fail because of an error in line 7.D  Compilation will always fail because of an error in line 8.

考题 单选题1. abstract class AbstractIt {  2. abstract float getFloat();  3. }  4. public class AbstractTest extends AbstractIt {  5. private float f1 = 1.0f;  6. private float getFloat() { return f1; }  7. }  What is the result?()A  Compilation succeeds.B  An exception is thrown.C  Compilation fails because of an error at line 2.D  Compilation fails because of an error at line 6.

考题 单选题class super {   public float getNum() {return 3.0f;}   }   public class Sub extends Super {   }   Which method, placed at line 6, will cause a compiler error?()A  Public float getNum() {return 4.0f; }B  Public void getNum (){}C  Public void getNum (double d){}D  Public double getNum (float d) {retrun 4.0f; }

考题 单选题1. class A {  2. public String toString ()  {  3. return “4”;  4. }  5. }  6. class B extends A {  7. public String toString ()   {  8. return super.toString()  + “3”;  9. }  10. }  11. public class Test {  12.   public static void main(String[]args)  {  13.      System.out.printIn(new B());  14.      }  15. }    What is the result?()A  Compilation succeeds and 4 is printed.B  Compilation succeeds and 43 is printed.C  An error on line 9 causes compilation to fail.D  An error on line 14 causes compilation to fail.E  Compilation succeeds but an exception is thrown at line 9.

考题 单选题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?()A  Line 33 must be called within a try block.B  The exception thrown by method1 in class a is not required to be caught.C  The method declared on line 31 must be declared to throw a RuntimeException.D  On line 5 of class a, the call to method2 of class b does not need to be placed in a try/catch block.

考题 单选题1. class Super {  2. public float getNum() { return 3.0f; }  3. }  4.   5. public class Sub extends Super {  6.   7. }  Which method, placed at line6, causes compilation to fail?()A  public void getNum(){}B  public void getNum(double d){}C  public float getNum() { return 4.0f; }D  public double getNum(float d) { return 4.0d; }

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class Super {  public int getLenght( ) { return 4; }  }  public class Sub extends Super {  public long getLenght( ) { return 5; }  public static void main(String[] args) {  Super sooper = new Super( );  Sub sub = new Sub( );  System.out.println(  sooper.getLenght( ) + “,” + sub.getLenght( ) );  }  } What is the output?()A  Just after line 13.B  Just after line 14.C  Just after line 15.D  Just after line 16 (that is, as the method returns).

考题 单选题1. class A {  3. public String to String() {  4. return “4”;  5. }  6. }  7. class B extends A {  8. public String toString() { 9. return super.toString() + “3”;  10. }  11. }  12. public class Test {  13. public static void main (String[] args) {  14. System.out.printIn(new B()); 15. }  16. }   What is the result( )?A  Compilation succeeds and 4 is printed.B  Compilation …………… is printed.C  An error on line 9 cause compilation to fail.D  An error on line 14 cause compilation to fail.E  Compilation succeeds but an exception is thrown at line 9.

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.