Java工程师笔试题和面试题答案(三)

|来源:新高考网

  When is the Float object, created in line 3,eligible for garbage collection?

  public class X{

  public Object m(){

  Object o = new Float(3.14F);//line 3

  Object [] oa = new Object[1];//line 4

  oa[0] = o;//line 5

  o=null;//line 6

  return oa[0];//line 7

  }

  }

  When is the Float object, created in line 3,eligible for garbage collection?

  A.just after line 5.

  B.just after line 6

  C.just after line 7(that is,as the method returns)

  D.never in this method

  12:

  What will happen when you attempt to compile and run the following code?

  public class Static

  {

  static

  {

  int x = 5;

  }

  static int x,y;

  public static void main(String args[])

  {

  x--;

  myMethod();

  System.out.println(x + y + ++x);

  }

  public static void myMethod()

  {

  y = x++ + ++x;

  }

  }

  Choices:

  What will happen when you attempt to compile and run the following code?

  public class Static

  {

  static

  {

  int x = 5;

  }

  static int x,y;

  public static void main(String args[])

  {

  x--;

  myMethod();

  System.out.println(x + y + ++x);

  }

  public static void myMethod()

  {

  y = x++ + ++x;

  }

  }

  Choices:

  A.prints : 2

  B.prints : 3

  C.prints : 7

  D.prints : 8

  13:假定a和b为int型变量,则执行下述语句组后,b的值为

  a=1;

  b=10;

  do

  {

  b-=a;

  a++;

  } while (b--<0);

  A.9

  B.-2

  C.-1

  D.8

  14:设有变量说明语句int a=1,b=0;

  则执行以下程序段的输出结果为( )。

  switch (a)

  {

  case 1:

  switch (b)

  {

  case 0:printf("*0*");break;

  case 1:printf("*1*");break;

  }

  case 2:printf("*2*");break;

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