单选题package test1;  public class Test1 {  static int x = 42;  }  package test2;  public class Test2 extends test1.Test1 {  public static void main(String[] args) { System.out.println(“x = “ + x);  }  }  What is the result?()Ax = 0Bx = 42CCompilation fails 

题目
单选题
package test1;  public class Test1 {  static int x = 42;  }  package test2;  public class Test2 extends test1.Test1 {  public static void main(String[] args) { System.out.println(“x = “ + x);  }  }  What is the result?()
A

 x = 0

B

 x = 42

C

 Compilation fails because of an error in line 2 of class Test2.

D

 Compilation fails because of an error in line 3 of class Test1.

E

 Compilation fails because of an error in line 4 of class Test2.


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更多“单选题package test1;  public class Test1 {  static int x = 42;  }  package test2;  public class Test2 extends test1.Test1 {  public static void main(String[] args) { System.out.println(“x = “ + x);  }  }  What is the result?()A  x = 0B  x = 42C  Compilation ”相关问题
  • 第1题:

    有以下源程序: package test; public class ClassA { int x=20; static int y=6; public static void main(String args[]) { ClassB b=new ClassB(); b.go(10); System.out.println("x="+b.x); } } class ClassB { int x; void go(int y) { ClassA a=new ClassA(); x=a.y; } } 上述源程序文件的运行结果为( )。

    A.x=10

    B.x=20

    C.x=6

    D.编译不通过


    正确答案:C
    解析:本题考查在Java中静态变量(类变量)的用法规则。对于static修饰的成员变量和成员方法,可以直接使用类名对它们进行访问。对于类变量,也就是static修饰的变量,在生成类的第一个实例对象时,Java运行时,系统对这个对象的每个类变量分配一块内存,以后再生成该类的实例对象时,所有实例对象将共享同一个类变量,每个实例对象对类变量的改变都会直接影响到其他实例对象,类变量除了可以通过类名直接访问外,还可以通过实例对象来访问。在本例中生成了一个staticinty=6类变量,在ClassA中调用的b.go(10),只不过是ClassB中的一个局部变量,通过调用ClassB中的go方法可以实现生成一个ClassA对象,并给这个新生成的对象赋予ClassA中的类变量y的值。

  • 第2题:

    package test1;  public class Test1 {  static int x = 42;  }  package test2;  public class Test2 extends test1.Test1 {  public static void main(String[] args) { System.out.println(“x = “ + x);  }  }  What is the result?() 

    • A、 x = 0
    • B、 x = 42
    • C、 Compilation fails because of an error in line 2 of class Test2.
    • D、 Compilation fails because of an error in line 3 of class Test1.
    • E、 Compilation fails because of an error in line 4 of class Test2.

    正确答案:C

  • 第3题:

    现有:  class Top  {     static int X=l;  public Top()  {  x*=3; }     }  class Middle extends Top  {      public  Middle()    {x+=l;  }  public static void main(String  []  args)  {     Middle m=new Middle();    System.out.println (x);    }     }  结果是什么?()    

    • A、  2
    • B、  3
    • C、  4
    • D、编译失败

    正确答案:C

  • 第4题:

    class TestA {  public void start() { System.out.println(”TestA”); }  }  public class TestB extends TestA {  public void start() { System.out.println(”TestB”); } public static void main(String[] args) {  ((TestA)new TestB()).start();  }  }  What is the result?() 

    • A、 TestA
    • B、 TestB
    • C、 Compilation fails.
    • D、 An exception is thrown at runtime.

    正确答案:B

  • 第5题:

    public class Test {  public static void main(String[] args) {  int x = 0;  assert (x > 0) ? “assertion failed” : “assertion passed”;  System.out.println(“Finished”);  }  }  What is the result?()  

    • A、 finished
    • B、 Compilation fails.
    • C、 An AssertionError is thrown and finished is output.
    • D、 An AssertionError is thrown with the message “assertion failed”.
    • E、 An AssertionError is thrown with the message “assertion passed”.

    正确答案:B

  • 第6题:

    public class Test {  private static int[] x;  public static void main(String[] args) {  System.out.println(x[0]);  }  }   What is the result?()   

    • A、 0
    • B、 null
    • C、 Compilation fails.
    • D、 A NullPointerException is thrown at runtime.
    • E、 An ArrayIndexOutOfBoundsException is thrown at runtime.

    正确答案:D

  • 第7题:

    public class Starter extends Thread {  private int x= 2;  public static void main(String[] args) throws Exception {  new Starter().makeItSo();  }  public Starter() {  x=5;  start();  }  public void makeItSo() throws Exception {  join();  x=x- 1;  System.out.println(x);  }  public void run() { x *= 2; }  }  What is the output if the main() method is rum?() 

    • A、 4
    • B、 5
    • C、 8
    • D、 9
    • E、 Compilation fails.
    • F、 An exception is thrown at runtime.
    • G、 It is impossible to determine for certain.

    正确答案:D

  • 第8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9题:

    单选题
    package test1;  public class Test1 {  static int x = 42;  }  package test2;  public class Test2 extends test1.Test1 {  public static void main(String[] args) { System.out.println(“x = “ + x);  }  }  What is the result?()
    A

     x = 0

    B

     x = 42

    C

     Compilation fails because of an error in line 2 of class Test2.

    D

     Compilation fails because of an error in line 3 of class Test1.

    E

     Compilation fails because of an error in line 4 of class Test2.


    正确答案: E
    解析: 暂无解析

  • 第10题:

    单选题
    现有:  class Top  {  static int x=l;  public Top (inty)  {  x*=3;  }      }  class Middle extends Top {      public Middle()  {x+=1;  )  public  static void main (String  []  args)  {      Middle m = new Middle();      System. out .println (x);      }     }      结果为:()
    A

    1

    B

    2

    C

    3

    D

    编译失败


    正确答案: B
    解析: 暂无解析

  • 第11题:

    单选题
    interface DeclareStuff{  public static final int EASY = 3;  void doStuff(int t); }  public class TestDeclare implements DeclareStuff {  public static void main(String [] args) {  int x=5;  new TestDeclare().doStuff(++x);  }  void doStuff(int s) {  s += EASY + ++s;  System.out.println(”s “ + s);  }  }  What is the result?()
    A

     s 14

    B

     s 16

    C

     s 10

    D

     Compilation fails.

    E

     An exception is thrown at runtime.


    正确答案: E
    解析: 暂无解析

  • 第12题:

    单选题
    现有:  class Top  {     static int X=l;  public Top()  {  x*=3; }     }  class Middle extends Top  {      public  Middle()    {x+=l;  }  public static void main(String  []  args)  {     Middle m=new Middle();    System.out.println (x);    }     }  结果是什么?()
    A

      2

    B

      3

    C

      4

    D

    编译失败


    正确答案: B
    解析: 暂无解析

  • 第13题:

    以下程序调试结果为:

    public class Test {

    int m=5;

    public void some(int x) {

    m=x;

    }

    public static void main(String args []) {

    new Demo().some(7);

    }

    }

    class Demo extends Test {

    int m=8;

    public void some(int x) {

    super.some(x);

    System.out.println(m);

    }

    }

    A.5

    B.8

    C.7

    D.无任何输出

    E.编译错误


    正确答案:B

  • 第14题:

    interface DeclareStuff{  public static final int EASY = 3;  void doStuff(int t); }  public class TestDeclare implements DeclareStuff {  public static void main(String [] args) {  int x=5;  new TestDeclare().doStuff(++x);  }  void doStuff(int s) {  s += EASY + ++s;  System.out.println(”s “ + s);  }  }  What is the result?() 

    • A、 s 14
    • B、 s 16
    • C、 s 10
    • D、 Compilation fails.
    • E、 An exception is thrown at runtime.

    正确答案:D

  • 第15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16题:

    class Top {  static int x = 1;  public Top(int y) { x *= 3; }  }  class Middle extends Top {  public Middle() { x += 1; }  public static void main(String [] args) {  Middle m = new Middle();  System.out.println(x);  }  }  结果为:() 

    • A、1
    • B、2
    • C、3
    • D、编译失败

    正确答案:D

  • 第17题:

    现有:  class Top  {  static int x=l;  public Top (inty)  {  x*=3;  }      }  class Middle extends Top {      public Middle()  {x+=1;  )  public  static void main (String  []  args)  {      Middle m = new Middle();      System. out .println (x);      }     }      结果为:()     

    • A、1
    • B、2
    • C、3
    • D、编译失败

    正确答案:D

  • 第18题:

    public class Test {  public static void main(String[] args) {  int x = 0;  assert (x > 0): “assertion failed”;  System.out.println(“finished”);  }  }  What is the result?()  

    • A、 finished
    • B、 Compilation fails.
    • C、 An AssertionError is thrown.
    • D、 An AssertionError is thrown and finished is output.

    正确答案:A

  • 第19题:

    单选题
    public class Test {  private static int[] x;  public static void main(String[] args) {  System.out.println(x[0]);  }  }   What is the result?()
    A

     0

    B

     null

    C

     Compilation fails.

    D

     A NullPointerException is thrown at runtime.

    E

     An ArrayIndexOutOfBoundsException is thrown at runtime.


    正确答案: B
    解析: 暂无解析

  • 第20题:

    单选题
    public class Starter extends Thread {  private int x= 2;  public static void main(String[] args) throws Exception {  new Starter().makeItSo();  }  public Starter() {  x=5;  start();  }  public void makeItSo() throws Exception {  join();  x=x- 1;  System.out.println(x);  }  public void run() { x *= 2; }  }  What is the output if the main() method is rum?()
    A

     4

    B

     5

    C

     8

    D

     9

    E

     Compilation fails.

    F

     An exception is thrown at runtime.

    G

     It is impossible to determine for certain.


    正确答案: D
    解析: 暂无解析

  • 第21题:

    单选题
    public class WhileFoo {  public static void main (String []args)   {  int x= 1, y = 6;  while (y--)  {x--;}  system.out.printIn(“x=” + x “y =” + y);  }  }   What is the result?()
    A

     The output is x = 6 y = 0

    B

     The output is x = 7 y = 0

    C

     The output is x = 6 y = -1

    D

     The output is x = 7 y = -1

    E

     Compilation will fail.


    正确答案: E
    解析: 暂无解析

  • 第22题:

    单选题
    public class Test {  public static void main(String[] args) {  int x = 0;  assert (x > 0) ? “assertion failed” : “assertion passed”;  System.out.println(“Finished”);  }  }  What is the result?()
    A

     finished

    B

     Compilation fails.

    C

     An AssertionError is thrown and finished is output.

    D

     An AssertionError is thrown with the message “assertion failed”.

    E

     An AssertionError is thrown with the message “assertion passed”.


    正确答案: E
    解析: 暂无解析

  • 第23题:

    单选题
    class Top {  static int x = 1;  public Top(int y) { x *= 3; }  }  class Middle extends Top {  public Middle() { x += 1; }  public static void main(String [] args) {  Middle m = new Middle();  System.out.println(x);  }  }  结果为:()
    A

    1

    B

    2

    C

    3

    D

    编译失败


    正确答案: B
    解析: 暂无解析

  • 第24题:

    单选题
    public class Test {  public static void main(String[] args) {  int x = 0;  assert (x > 0): “assertion failed”;  System.out.println(“finished”);  }  }  What is the result?()
    A

     finished

    B

     Compilation fails.

    C

     An AssertionError is thrown.

    D

     An AssertionError is thrown and finished is output.


    正确答案: D
    解析: This question is a bit tricky because it lacks the following information: It should include a statement that says whether or not assertions are enabled. If they are indeed enabled, the 
    correction answer is C. but if they are not, the correct answer is A. Assertions are not enabled by default so if the question is not changed, the most logical answer is A.