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; }

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; }


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public class SomeException {  } Class a:  public class a {  public void doSomething() { }  } Class b:  public class b extends a {  public void doSomething() throws SomeException { }  }  Which is true about the two classes?() A、 Compilation of both classes will fail.B、 Compilation of both classes will succeed.C、 Compilation of class a will fail. Compilation of class b will succeed.D、 Compilation of class a will fail. Compilation of class a will succeed.

1. class A {  2. public int getNumber(int a) {  3.     return a + 1;  4. }  5. }  6.    7. class B extends A {  8. public int getNumber (int a) {  9. return a + 2  10. }  11.    12. public static void main (String args[])  {  13. A a = new B();  14. System.out.printIn(a.getNumber(0));  15.    } 16. }     What is the result?()  A、 Compilation succeeds and 1 is printed.B、 Compilation succeeds and 2 is printed.C、 An error at line 8 causes compilation to fail.D、 An error at line 13 causes compilation to fail.E、 An error at line 14 causes compilation to fail.

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.

class A {   public String toString () {   return “4”;   }   }   class B extends A {   8. public String toString () {   return super.toString() + “3”;   }   }   public class Test {   public static void main(Stringargs) {   System.out.printIn(new B());   }   }   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.

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; }

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; }

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.

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.

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; }

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.

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.

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.

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; }

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.

class super (   public int I = 0;   public super (string text) (   I = 1   )   )     public class sub extends super (   public sub (string text) (   i= 2   )   public static void main (straing args) (  sub sub = new sub (“Hello”);   system.out. PrintIn(sub.i);  )   )   What is the result?()A、 Compilation will fail.B、 Compilation will succeed and the program will print “0”C、 Compilation will succeed and the program will print “1”D、 Compilation will succeed and the program will print “2”

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.

单选题class super (  public int I = 0;  public super (string text) (  I = 1  )  )  public class sub extends super (  public sub (string text)   ( i= 2  )  public static void main (straing args[])   (  sub sub = new sub (“Hello”);  system.out. PrintIn(sub.i);  )    )   What is the result?()A Compilation will fail.B Compilation will succeed and the program will print “0”C Compilation will succeed and the program will print “1”D Compilation will succeed and the program will print “2”

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.

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; }

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.

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.

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; }

单选题public class SomeException {  } Class a:  public class a {  public void doSomething() { }  } Class b:  public class b extends a {  public void doSomething() throws SomeException { }  }  Which is true about the two classes?()A Compilation of both classes will fail.B Compilation of both classes will succeed.C Compilation of class a will fail. Compilation of class b will succeed.D Compilation of class a will fail. Compilation of class a will succeed.

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.

单选题1. class A {  2. public int getNumber(int a) {  3.     return a + 1;  4. }  5. }  6.    7. class B extends A {  8. public int getNumber (int a) {  9. return a + 2  10. }  11.    12. public static void main (String args[])  {  13. A a = new B();  14. System.out.printIn(a.getNumber(0));  15.    } 16. }     What is the result?()A Compilation succeeds and 1 is printed.B Compilation succeeds and 2 is printed.C An error at line 8 causes compilation to fail.D An error at line 13 causes compilation to fail.E An error at line 14 causes compilation to fail.

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.

单选题class A {   public String toString () {   return “4”;   }   }   class B extends A {   8. public String toString () {   return super.toString() + “3”;   }   }   public class Test {   public static void main(Stringargs) {   System.out.printIn(new B());   }   }   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.

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; }