Q18
Given：
1  pubic class ArrayTest {
2      public static void main(String[] args{
3          float f1[],f2[];
4          f1 = new float[1];
5          f2 = f1;
6          System.out.println("f2[0] = "+ f2[0]);
7       }
8  }
What is the result?
A  It prints f2[0] = 0.0;
B  It prints f2[0] = NaN;
C  An error at line 5 causes compile to fail.
D  An error at line 6 causes compile to fail.
E  An error at line 6 causes an exceptation at run time;

Q19  Given:
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.

Q2 Given:
class Super {
     public float getNum(){
           return 3.0f;
      }
}
public class Sub extends Super {
6
}
Which method,placeed at line 6,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;}

Q21 Given:
boolean bool = true;
if(bool = false) {
     System.out.println("a");
}else if(bool){
     System.out.println("b");
}else if(!bool){
     System.out.println("c");
}else{
     System.out.println("d");
}
What is true？
A  a
B  b
C  c
D  d
E  Compilation fails.

Q22
Which statement is true?
A  catch(X x) can catch subclasses of X;
B  The Error class is a RuntimeException;
C  Any statement that can throw an Error must be inclosed  in a try block;
D  Any statement that can throw an Exception must be inclosed  in a try block;
E  Any statement that can throw a RuntimeException must be inclosed  in a try block;

Answer: 18 A  19  D  20  A  21  E  22 A

答案正确吗？求解答？

18 A  19  D  20  A  21  E  22 E

答案正确
楼上的22题  RuntimeException没必要try