JAVA题库:格林模拟试题二(上)(2)
来源:优易学  2010-1-11 12:02:19   【优易学:中国教育考试门户网】   资料下载   IT书店

question 4)

what will happen when you attempt to compile and run this code?

class base{
abstract public void myfunc();
public void another(){
system.out.println("another method");
}
}

public class abs extends base{
public static void main(string argv[]){
abs a = new abs();
a.amethod();
}

public void myfunc(){
system.out.println("my func");
}

public void amethod(){
myfunc();
}
}

1) the code will compile and run, printing out the words "my func"
2) the compiler will complain that the base class is not declared as abstract.
3) the code will compile but complain at run time that the base class has non abstract methods
4) the compiler will complain that the method myfunc in the base class has no body, nobody at all to looove it


question 5)

why might you define a method as native?

1) to get to access hardware that java does not know about
2) to define a new data type such as an unsigned integer
3) to write optimised code for performance in a language such as c/c++
4) to overcome the limitation of the private scope of a method


question 6)

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();
}
}

1) compile time error indicating that a class with any final methods must be declared final itself
2) compile time error indicating that you cannot inherit from a class with final methods
3) run time error indicating that base is not defined as final
4) success in compilation and output of "amethod" at run time.

责任编辑:cyth

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