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?()ACompilation will succeed if a extends b.BCompilation will succe

题目
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.


相似考题
更多“1. class SuperClass {  2. public a geta() {  3. return new a”相关问题
  • 第1题:

    设有程序如下: public class jzh0319 { public static void main(String args[]) { subClass sc=new subClass(); } } class superClass { superClass() { System.out.println("父类");} } class subClass extends superClass { subClass() {System.out.println("子类"); } } 其输出结果只有一行。()

    此题为判断题(对,错)。


    答案:错

  • 第2题:

    1. public class Outer{  2. public void someOuterMethod() {  3. // Line 3  4. }  5. public class Inner{}  6. public static void main( String[]argv ) {  7. Outer o = new Outer();  8. // Line 8  9. }  10. }  Which instantiates an instance of Inner?()  

    • A、 new Inner(); // At line 3
    • B、 new Inner(); // At line 8
    • C、 new o.Inner(); // At line 8
    • D、 new Outer.Inner(); // At line 8

    正确答案:A

  • 第3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.

    正确答案:C

  • 第4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.

    正确答案:B

  • 第5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.

    正确答案:B

  • 第6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.

    正确答案:A

  • 第7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; }

    正确答案:B

  • 第8题:

    1. public class A {  2. public String doit(int x, int y) {  3. return “a”;  4. }  5.  6. public String doit(int... vals) {  7. return “b”;  8. } 9. }  Given:  25. A a=new A();  26. System.out.println(a.doit(4, 5));  What is the result?() 

    • A、 Line 26 prints “a” to System.out.
    • B、 Line 26 prints „b” to System.out.
    • C、 An exception is thrown at line 26 at runtime.
    • D、 Compilation of class A will fail due to an error in line 6.

    正确答案:A

  • 第9题:

    多选题
    Class TestException  1. public class TestException extends Exception {  2. } Class a:  1. public class a {  2.  3. public String sayHello(String name) throws TestException {  4.  5. if(name == null) {  6. throw new TestException();  7. }  8.  9. return “Hello “+ name;  10. }  11.  12. }  A programmer wants to use this code in an application: 45. A a=new A();  46. System.out.println(a.sayHello(”John”));  Which two are true?()
    A

    Class a will not compile.

    B

    Line 46 can throw the unchecked exception TestException.

    C

    Line 45 can throw the unchecked exception TestException.

    D

    Line 46 will compile if the enclosing method throws a TestException.

    E

    Line 46 will compile if enclosed in a try block, where TestException is caught.


    正确答案: A,C
    解析: 暂无解析

  • 第10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 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; }


    正确答案: D
    解析: 暂无解析

  • 第11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.


    正确答案: B
    解析: 暂无解析

  • 第12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?()
    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.


    正确答案: D,C
    解析: 暂无解析

  • 第13题:

    1. public class ReturnIt {  2. return Type methodA(byte x, double y) {  3. return (long)x / y * 2;  4. }  5. }  What is the narrowest valid returnType for methodA in line2?()  

    • A、 int
    • B、 byte
    • C、 long
    • D、 short
    • E、 float
    • F、 double

    正确答案:F

  • 第14题:

    1. public class Target {  2. private int i = 0;  3. public int addOne() {  4. return ++i;  5. }  6. }  And:  1. public class Client {  2. public static void main(String[] args) {  3. System.out.println(new Target().addOne());  4. }  5. }  Which change can you make to Target without affecting Client?() 

    • A、 Line 4 of class Target can be changed to return i++;
    • B、 Line 2 of class Target can be changed to private int i = 1;
    • C、 Line 3 of class Target can be changed to private int addOne() {
    • D、 Line 2 of class Target can be changed to private Integer i = 0;

    正确答案:D

  • 第15题:

    Class TestException  1. public class TestException extends Exception {  2. } Class a:  1. public class a {  2.  3. public String sayHello(String name) throws TestException {  4.  5. if(name == null) {  6. throw new TestException();  7. }  8.  9. return “Hello “+ name;  10. }  11.  12. }  A programmer wants to use this code in an application: 45. A a=new A();  46. System.out.println(a.sayHello(”John”));  Which two are true?()

    • A、 Class a will not compile.
    • B、 Line 46 can throw the unchecked exception TestException.
    • C、 Line 45 can throw the unchecked exception TestException.
    • D、 Line 46 will compile if the enclosing method throws a TestException.
    • E、 Line 46 will compile if enclosed in a try block, where TestException is caught.

    正确答案:D,E

  • 第16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.

    正确答案:C

  • 第17题:

    现有:   1. class Synapse {    2.    protected int gap() { return 7; }    3. }   4.     5. class Creb extends Synapse {    6.   // insert code here   7. }    分别插入到第 6 行,哪三行可以编译?()

    • A、 int gap() { return 7; }
    • B、 public int gap() { return 7; }
    • C、 private int gap(int x) { return 7; }
    • D、 protected Creb gap() { return this; }
    • E、 public int gap() { return Integer.getInteger ("42"); }

    正确答案:B,C,E

  • 第18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(); }

    正确答案:C,E

  • 第19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?()  

    • A、 InsideOnew ei= eo.new InsideOn();
    • B、 Eo.InsideOne ei = eo.new InsideOne();
    • C、 InsideOne ei = EnclosingOne.new InsideOne();
    • D、 EnclosingOne.InsideOne ei = eo.new InsideOne();

    正确答案:D

  • 第20题:

    多选题
    1. class SuperFoo {  2. SuperFoo doStuff(int x) {  3. return new SuperFoo(); 4. }  5. }  6.  7. class Foo extends SuperFoo {  8. //insert code here  9. }   下面哪三项分别插入到第8行,可以编译?()
    A

    int doStuff() { return 42; }

    B

    int doStuff(int x) { return 42; }

    C

    Foo doStuff(int x) { return new Foo(); }

    D

    SuperFoo doStuff(int x) { return new Foo(); }


    正确答案: D,C
    解析: 暂无解析

  • 第21题:

    单选题
    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?()
    A

     InsideOnew ei= eo.new InsideOn();

    B

     Eo.InsideOne ei = eo.new InsideOne();

    C

     InsideOne ei = EnclosingOne.new InsideOne();

    D

     EnclosingOne.InsideOne ei = eo.new InsideOne();


    正确答案: C
    解析: 暂无解析

  • 第22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; }


    正确答案: A
    解析: 暂无解析

  • 第23题:

    多选题
    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(); }


    正确答案: C,A
    解析: 暂无解析