class A {   public int getNumber(int a) {   return a + 1;   }   }    class B extends A {   public int getNumber (int a) {   return a + 2   }    public static void main (String args) {   A a = new B();   System.out.printIn(a.getNumber(0));   }   }   What 

题目

class A {   public int getNumber(int a) {   return a + 1;   }   }    class B extends A {   public int getNumber (int a) {   return a + 2   }    public static void main (String args) {   A a = new B();   System.out.printIn(a.getNumber(0));   }   }   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.

相似考题
更多“class A {   public int getNumber(int a) {   return a + 1;   }   }    class B extends A {   public int getNumber (int a) {   return a + 2   }    public static void main (String args) {   A a = new B();   System.out.printIn(a.getNumber(0));   }   }   What i”相关问题
  • 第1题:

    能将程序补充完整的选项是 class Person { private int a; public int change(int m){return m; } } public class Teacher extends Person { public int b; public static void main(String arg[]) { Person p=new Person(); Teacher t=new Teacher(); int i; ______ } }

    A.i=m

    B.i=b

    C.i=p.a

    D.i=p.change(50)


    正确答案:D
    解析:本题考查类的声明。选项A中m没有被声明过,不能使用;选项B中虽然b是类Teacher的public成员变量,但在静态方法中,不能使用类中的非静态成员;选项C中a是类Person的private成员,在类外不能直接引用;选项D中change(int m)方法是public方法,并且返回一个int型值,可以通过类的实例变量p引用并赋值给一个int型变量。

  • 第2题:

    下列程序的执行结果是 ( ) public class ex68{ public static void main(String[]args){ ex68 obj=new ex68(); int s=0; for(int i=1;i<=4;i++){ s+=obj.method(i); } System.out.println(s); } public int method(int n){ if(n==1) return 1; else return n*method(n-1); } }

    A.3

    B.9

    C.33

    D.153


    正确答案:C
    解析:该题考查的是递归调用。在Java中允许方法的递归调用,即允许方法调用自身。当算阶乘的时候最多的是用到递归调用,本题算的是从1到4的递归的和。

  • 第3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4题:

    class super {  public int getLength()  {return 4;}  }  public class Sub extends Super {  public long getLength() {return 5;}  public static void main (String[]args)  {  super sooper = new Super ();  Sub sub = new Sub();  System.out.printIn(  sooper.getLength()+ “,” + sub.getLength()   };  }  What is the output?()  

    • A、 4, 4
    • B、 4, 5
    • C、 5, 4
    • D、 5, 5
    • E、 The code will not compile.

    正确答案:E

  • 第5题:

    class A {   public byte getNumber () {   return 1;   }   }   class B extends A {   public short getNumber() {   return 2;   }    public static void main (String args) {   B b = new B ();    System.out.printIn(b.getNumber())  }   }   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 14 causes compilation to fail.
    • E、 Compilation succeeds but an exception is thrown at line 14.

    正确答案:C

  • 第6题:

    public class test(    public int aMethod()[   static int i=0;   i++;   return I;   )    public static void main (String args){   test test = new test();    test.aMethod();   int j = test.aMethod();   System.out.printIn(j);   ]  }   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”

    正确答案:D

  • 第7题:

    1) class Person {  2) public void printValue(int i, int j) {/*…*/ }     3) public void printValue(int i){/*...*/ }     4) }  5) public class Teacher extends Person {     6) public void printValue() {/*...*/ }     7) public void printValue(int i) {/*...*/}     8) public static void main(String args[]){     9) Person t = new Teacher();     10) t.printValue(10);     11) }    12) }  Which method will the statement on line 10 call? ()  

    • A、 on line 2
    • B、 on line 3
    • C、 on line 6
    • D、 on line 7

    正确答案:D

  • 第8题:

    class A {  public byte getNumber() {  return 1;  }  }  class B extends A {  public short getNumber() {  return 2;  }  public static void main(String args[]) {  B b = new B();  System.out.println(b.getNumber()); }  }   What is the result?()

    • A、 1
    • B、 2
    • C、 An exception is thrown at runtime.
    • D、 Compilation fails because of an error in line 8.
    • E、 Compilation fails because of an error in line 14.

    正确答案:D

  • 第9题:

    单选题
    class A {  public byte getNumber() {  return 1;  }  }  class B extends A {  public short getNumber() {  return 2;  }  public static void main(String args[]) {  B b = new B();  System.out.println(b.getNumber()); }  }   What is the result?()
    A

     1

    B

     2

    C

     An exception is thrown at runtime.

    D

     Compilation fails because of an error in line 8.

    E

     Compilation fails because of an error in line 14.


    正确答案: D
    解析: getNumber() in B cannot override getNumber() in A; attempting to use incompatible return type: short to byte. 

  • 第10题:

    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(String args[]) {  Sub sub = new Sub(“Hello”);  System.out.println(sub.i);  }  }  What is the result?()
    A

     0

    B

     1

    C

     2

    D

     Compilation fails.


    正确答案: B
    解析: This code is perfectly legal and the answer is C. 

  • 第11题:

    单选题
    class super {  public int getLength()  {return 4;}  }  public class Sub extends Super {  public long getLength() {return 5;}  public static void main (String[]args)  {  super sooper = new Super ();  Sub sub = new Sub();  System.out.printIn(  sooper.getLength()+ “,” + sub.getLength()   };  }  What is the output?()
    A

     4, 4

    B

     4, 5

    C

     5, 4

    D

     5, 5

    E

     The code will not compile.


    正确答案: C
    解析: 暂无解析

  • 第12题:

    单选题
    public class test (      private static int j = 0;  private static boolean methodB(int k) (  j += k;  return true;  )  public static void methodA(int  i)(  boolean b:     b = i < 10 | methodB (4);  b = i < 10 || methodB (8);  )  public static void main (String args[])(   methodA (0);  system.out.printIn(j);  )  )   What is the result?()
    A

     The program prints “0”

    B

     The program prints “4”

    C

     The program prints “8”

    D

     The program prints “12”

    E

     The code does not complete.


    正确答案: B
    解析: 暂无解析

  • 第13题:

    interface A{

    int x = 0;

    }

    class B{

    int x =1;

    }

    class C extends B implements A {

    public void pX(){

    System.out.println(x);

    }

    public static void main(String[] args) {

    new C().pX();

    }

    }


    正确答案:

     

    错误。在编译时会发生错误(错误描述不同的JVM 有不同的信息,意思就是未明确的

    x 调用,两个x 都匹配(就象在同时import java.util 和java.sql 两个包时直接声明Date 一样)。

    对于父类的变量,可以用super.x 来明确,而接口的属性默认隐含为 public static final.所以可

    以通过A.x 来明确。

  • 第14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.

    正确答案:B

  • 第15题:

    Which are syntactically valid statement at// point x?()     class Person {     private int a;  public int change(int m){  return m;  }     }  public class Teacher extends Person {     public int b;  public static void main(String arg[]){     Person p = new Person();     Teacher t = new Teacher();    int i;  // point x     }    } 

    • A、 i = m;
    • B、 i = b;
    • C、 i = p.a;
    • D、 i = p.change(30);
    • E、 i = t.b.

    正确答案:D,E

  • 第16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(String args[]) {  Sub sub = new Sub(“Hello”);  System.out.println(sub.i);  }  }  What is the result?()  

    • A、 0
    • B、 1
    • C、 2
    • D、 Compilation fails.

    正确答案:C

  • 第17题:

    public class Test {  public static void leftshift(int i, int j) {  i<<=j;  }  public static void main(String args[])  {  int i = 4, j = 2;  leftshift(i, j);   System.out.printIn(i); }  }     What is the result?()  

    • A、 2
    • B、 4
    • C、 8
    • D、 16
    • E、 The code will not compile.

    正确答案:B

  • 第18题:

    public class Test {  public int aMethod() {  static int i = 0;  i++;  return i;  }  public static void main (String args[]) {  Test test = new Test();  test.aMethod();  int j = test.aMethod();  System.out.println(j);  }  }  What is the result?()  

    • A、 0
    • B、 1
    • C、 2
    • D、 Compilation fails.

    正确答案:D

  • 第19题:

    public class test (      private static int j = 0;  private static boolean methodB(int k) (  j += k;  return true;  )  public static void methodA(int  i)(  boolean b:     b = i < 10 | methodB (4);  b = i < 10 || methodB (8);  )  public static void main (String args[])(   methodA (0);  system.out.printIn(j);  )  )   What is the result?()  

    • A、 The program prints “0”
    • B、 The program prints “4”
    • C、 The program prints “8”
    • D、 The program prints “12”
    • E、 The code does not complete.

    正确答案:B

  • 第20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”

    正确答案:A

  • 第21题:

    多选题
    Which are syntactically valid statement at// point x?()     class Person {     private int a;  public int change(int m){  return m;  }     }  public class Teacher extends Person {     public int b;  public static void main(String arg[]){     Person p = new Person();     Teacher t = new Teacher();    int i;  // point x     }    }
    A

    i = m;

    B

    i = b;

    C

    i = p.a;

    D

    i = p.change(30);

    E

    i = t.b.


    正确答案: C,D
    解析: A:m没有被申明过,不能使用。 
    B:虽然b是类Teacher的public成员变量,但是在静态方法中不能使用类中的非静态成员。 
    C://a是类Person的private成员,在类外不能直接引用。 
    D://change(int m)方法是public方法,并且返回一个int型值,可以通过类的实例变量p引用并赋值给一个int型变量。 
    E://b是类Teacher的public成员变量,且是int型,可以通过类的实例变量t引用并赋值给一个int型变量

  • 第22题:

    单选题
    public class Test {  public int aMethod() {  static int i = 0;  i++;  return i;  }  public static void main (String args[]) {  Test test = new Test();  test.aMethod();  int j = test.aMethod();  System.out.println(j);  }  }  What is the result?()
    A

     0

    B

     1

    C

     2

    D

     Compilation fails.


    正确答案: D
    解析: 暂无解析

  • 第23题:

    单选题
    public class Test {  public static void leftshift(int i, int j) {  i<<=j;  }  public static void main(String args[])  {  int i = 4, j = 2;  leftshift(i, j);   System.out.printIn(i); }  }     What is the result?()
    A

     2

    B

     4

    C

     8

    D

     16

    E

     The code will not compile.


    正确答案: C
    解析: 暂无解析