Java interview questions Part21

3.
Which is true? (Choose all that apply. )

"X extends Y" is correct if and only if X is a class and Y is an interface.

"X extends Y" is correct if and only if X is an interface and Y is a class.

"X extends Y" is correct if X and Y are either both classes or both interfaces.

"X extends Y" is correct for all combinations of X and Y being classes and/or interfaces.


4.
Which are valid declarations? (Choose all that apply.)

int $x;

int 123;

int _123;

int #dim;

int %percent;

int *divide;

int central_sales_region_Summer_2005_gross_sales;


5.
Which method names follow the JavaBeans standard? (Choose all that apply.)

addSize

getCust

deleteRep

isColorado

putDimensions


6.
Given:

1. class Voop {
2. public static void main(String [] args) {
3. doStuff(1);
4. doStuff(1, 2);
5. }
6. // insert code here
7. }

Which, inserted independently at line 6, will compile? (Choose all that apply.)

static void doStuff(int... doArgs) { }

static void doStuff (int [] doArgs) { }

static void doStuff(int doArgs...) { }

static void doStuff(int... doArgs, int y) { }

static void doStuff(int x, int... doArgs) { }


7.
Which are legal declarations? (Choose all that apply. )

short x [];

short [] y;

short [5] x2;

short z2 [5];

short [] z [] [];

short [] y2 = [5];



8.
Given:

1. enum Animals {
2. DOG ("woof"), CAT ("meow"), FISH ("burble");
3. String sound;
4. Animals(String s) { sound = s; }
5. }
6. class TestEnum {
7. static Animals a;
8. public static void main(String[] args) {
9. System.out.println(a.DOG.sound + " " + a.FISH.sound);
10. }
11. }

What is the result?

woof burble

Multiple compilation errors

Compilation fails due to an error on line 2

Compilation fails due to an error on line 3

Compilation fails due to an error on line 4

Compilation fails due to an error on line 9



9.
Given:

1. enum A { A }
2. class E2 {
3. enum B { B }
4. void C() {
5. enum D { D }
6. }
7. }

Which statements are true? (Choose all that apply.)

The code compiles.

If only line 1 is removed the code compiles.

If only line 3 is removed the code compiles.

If only line 5 is removed the code compiles.

If lines 1 and 3 are removed the code compiles

If lines 1, 3 and 5 are removed the code compiles