开发学院WEB开发Jsp SCJP模拟题104道 阅读

SCJP模拟题104道

 2008-01-05 18:22:36 来源:WEB开发网   
核心提示: Simulated Test of SCJP for java2 PlatFORM (only for training) 1. 1) public class ReturnIt{ 2) returnType methodA(byte x, double y){

   Simulated Test of SCJP for java2 PlatFORM
   (only for training)
  
  
  1. 1) public class ReturnIt{
   2) returnType methodA(byte x, double y){
   3) return (short)x/y*2;
   4) }
   5) }
   what is valid returnType for methodA in line 2?
  Answer:double
  
  2. 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){return 4.0d;}
  Answer:B
  
  3. public class IfTest{
   public static void main(String args[]){
   int x=3;
   int y=1;
   if(x=y)
   System.out.PRintln("Not equal");
   else
   System.out.println("Equal");
   }
   }
   what is the result?
  Answer:compile error
  
  4. public class Foo{
   public static void main(String args[]){
   try{return;}
   finally{ System.out.println("Finally");}
   }
   }
   what is the result?
   A. print out nothing
   B. print out "Finally"
   C. compile error
  Answer:B
  
  5. public class Test{
   public static String output="";
   public static void foo(int i){
   try {
  if(i==1){
  throw new Exception();
  }
  output +="1";
   }
   catch(Exception e){
   output+="2";
   return;
   }
   finally{
   output+="3";
   }
   output+="4";
   }
   public static void main(String args[]){
   foo(0);
   foo(1);
   24)
   }
   }
   what is the value of output at line 24?
  
  Answer:13423
  
  6. public class IfElse{
   public static void main(String args[]){
   if(odd(5))
   System.out.println("odd");
   else
   System.out.println("even");
   }
   public static int odd(int x){return x%2;}
   }
   what is output?
  
  
  Answer:Compile Error
  
  
  7. class ExceptionTest{
   public static void main(String args[]){
   try{
  methodA();
  }
   catch(IOException e){
  System.out.println("caught IOException");
   }
   catch(Exception e){
   System.out.println("caught Exception");
   }
   }
   }
   If methodA() throws a IOException, what is the result?
  Answer:caught IOException
  exception can catch once only
  if change the sequence of catch
   catch(IOException e) can't execute and compiler will report rongyu error
  
  
  8. int i=1,j=10;
   do{
   if(i++>--j) continue;
   }while(i<5);
  After Execution, what are the value for i and j?
  A. i=6 j=5
  B. B.i=5 j=5
  C. i=6 j=4
  D. i=5 j=6
  E. i=6 j=6
  Answer:D
  
  
  9. 1)public class X{
   2) public Object m(){
   3) Object o=new Float(3.14F);
   4) Object[] oa=new Object[1];
   5) oa[0]=o;
   6) o=null;
   7) oa[0]=null;
   System.out.println(oa[0]);
   9) }
   10) }
   which line is the earliest point the object a refered is definitely elibile
   to be garbage collectioned?
   A.After line 4 B. After line 5 C.After line 6
   D.After line 7 E.After line 9(that is,as the method returns)
  Answer:D
  
  
  10. 1) interface Foo{
   2)int k=0;
   3) }
   4) public class Test implements Foo{
   5) public static void main(String args[]){
   6)int i;
   7)Test test =new Test();
   8)i=test.k;
   9)i=Test.k;
   10)i=Foo.k;
   11) }
   12) }
   what is the result?
  Answer:compile sUCcessed and i=0
  
  11. what is reserved Words in java?
   A. run
   B. default
   C. implement
   D. import
  Answer:B,D
  
  12. public class Test{
   public static void main(String[] args){
   String foo=args[1];
   Sring bar=args[2];
   String baz=args[3];
   }
   }
   java Test Red Green Blue
   what is the value of baz?
   A. baz has value of ""
   B. baz has value of null
   C. baz has value of "Red"
   D. baz has value of "Blue"
   E. baz has value of "Green"
   F. the code does not compile
   G. the program throw an exception
  Answer:G
  
  13. int index=1;
   int foo[]=new int[3];
   int bar=foo[index];
   int baz=bar+index;
   what is the result?
   A. baz has a value of 0
   B. baz has value of 1
   C. baz has value of 2
   D. an exception is thrown
   E. the code will not compile
  Answer:B
  
  14. which three are valid declaraction of a float?
   A. float foo=-1;
   B. float foo=1.0;
   C. float foo=42e1;
   D. float foo=2.02f;
   E. float foo=3.03d;
   F. float foo=0x0123;
  Answer:A,D,F
  
  15. public class Foo{
   public static void main(String args[]){
   String s;
   System.out.println("s="+s);
   }
   }
   what is the result?
  Answer:compile error
  
  16. 1) public class Test{
   2) public static void main(String args[]){
   3) int i=oxFFFFFFF1;
   4) int j=~i;
   5)
   6) }
   7) }
   which is decimal value of j at line 5?
   A. 0 B.1 C.14 D.-15 E. compile error at line 3
   F. compile error at line 4
  Answer:C
  
  17. float f=4.2F;
   Float g=new Float(4.2F);
   Double d=new Double(4.2);
   Which are true?
   A. f==g B. g==g C. d==f D. d.equals(f) E d.equals(g) F. g.equals(4.2);
  Answer:B,E
  
  18. public class Test{
   public static void add3(Integer i){
   3) int val=i.intvalue();
   val+=3;
   i=new Integer(val);
   }
   public static void main(String args[]){
   Integer i=new Integer(0);
   add3(i);
   System.out.println(i.intvalue());
   }
   }
   what is the result?
   A. compile fail B.print out "0" C.print out "3"
   D.compile succeded but exception at line 3
  Answer:B
  
  19. public class Test{
   public static void main(String[] args){
   System.out.println(6^3);
   }
   }
   what is output?
  Answer:5
  ^ is yi huo
  
  20. public class Test{
   public static void stringReplace(String text){
   text=text.replace('j','l');
   }
   public static void bufferReplace(StringBuffer text){
   text=text.append("c");
   }
   public static void main(String args[]){
   String textString=new String("java");
   StringBuffer textBuffer=new StringBuffer("java");
   StringReplace(textString);
   bufferReplace(textBuffer);
   System.out.println(textString+textBuffer);
   }
   }
   what is the output?
  Answer:javajavac
  
  21. public class ConstOver{
   public ConstOver(int x, int y, i

Tags:SCJP 模拟题

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