Test of the Java Skill（1）

核心提示： Question 1: What will happen when you attempt to compile and run this code? class Base{ public final void amethod(){ System.out.PRintln(“amethod”); } }

　　 Question 1:
　　 What will happen when you attempt to compile and run this code?
　　 class Base{
　　 public final void amethod(){
　　 System.out.PRintln(“amethod”);
　　 }
　　 }

　　 public class Fin extends Base{
　　 public static void main(String argv[]){
　　 Base b = new Base();
　　 b.amethod();
　　 }
　　 }

　　 A. Compile time error indicating that a class with any final methods must be declared final itself

　　 B. Compile time error indicating that you cannot inherit from a class with final methods

　　 C. Run time error indicating that Base is not defined as final

　　 D. SUCcess in compilation and output of “amethod” at run time

　　 Question 2:
　　 Given the following code what will be output?

　　 public class Pass{
　　 static int j = 20;
　　 public static void main(String argv[]){
　　 int i=10;
　　 Pass p = new Pass();

　　 p.amethod(i);
　　 System.out.println(i);
　　 System.out.println(j);
　　 }

　　 public void amethod(int x){
　　 x=x*2;
　　 j=j*2;
　　 }
　　 }

　　 A. Error: amethod parameter does not match variable

　　 B. 20 and 40

　　 C. 10 and 40

　　 D. 10 and 20

　　 Question 3:
　　 What happens when you attempt to compile and run these two files in the same Directory?

　　 // File P1.java

　　 package MyPackage;
　　 class P1{
　　 void afancymethod(){
　　 System.out.println(“what a fancy method”);
　　 }
　　 }

　　 // File P2.java

　　 public class P2 extends P1{
　　 afancymethod();
　　 }

　　 A. Both compile and P2 outputs “what a fancy method” when run

　　 B. Neither will compile

　　 C. Both compile but P2 has an error at run time

　　 D. P1 compiles cleanly but P2 has an error at compile time

　　 Question 4:
　　 Which statement declares a variable a which is suitable for
referring to an array of 50 string objects?

　　 A. char a[][];

　　 B. String a[];

　　 C. String []a;

　　 D. Object a[50];

　　 E. String a[50];

　　 Question 5:
　　 Given the following declaration
　　 String s = "Example";
　　 Which are legal code?

　　 A. s >>> = 3;