Language Fundamentals - General Questions (2)

Which three are legal array declarations?

1 int [] myScores [];

2 char [] myChars;

3 int [6] myScores;

4 Dog myDogs [];

5 Dog myDogs [7];

A.	1, 2, 4
B.	2, 4, 5
C.	2, 3, 4
D.	All are correct.

Answer: Option A

Explanation:

(1), (2), and (4) are legal array declarations. With an array declaration, you can place the brackets to the right or left of the identifier. Option A looks strange, but it's perfectly legal to split the brackets in a multidimensional array, and place them on both sides of the identifier. Although coding this way would only annoy your fellow programmers, for the exam, you need to know it's legal.

(3) and (5) are wrong because you can't declare an array with a size. The size is only needed when the array is actually instantiated (and the JVM needs to know how much space to allocate for the array, based on the type of array and the size).

10.

Which is a valid keyword in java?

A.	interface
B.	string
C.	Float
D.	unsigned

Answer: Option A

Explanation:

interface is a valid keyword.

Option B is wrong because although "String" is a class type in Java, "string" is not a keyword.

Option C is wrong because "Float" is a class type. The keyword for the Java primitive is float.

Option D is wrong because "unsigned" is a keyword in C/C++ but not in Java.

11.

Which is a reserved word in the Java programming language?

A.	method
B.	native
C.	subclasses
D.	reference
E.	array

Answer: Option B

Explanation:

The word "native" is a valid keyword, used to modify a method declaration.

Option A, D and E are not keywords. Option C is wrong because the keyword for subclassing in Java is extends, not 'subclasses'.

12.

Which will legally declare, construct, and initialize an array?

A.	int [] myList = {"1", "2", "3"};
B.	int [] myList = (5, 8, 2);
C.	int myList [] [] = {4,9,7,0};
D.	int myList [] = {4, 3, 7};

Answer: Option D

Explanation:

The only legal array declaration and assignment statement is Option D

Option A is wrong because it initializes an int array with String literals.

Option B is wrong because it use something other than curly braces for the initialization.

Option C is wrong because it provides initial values for only one dimension, although the declared array is a two-dimensional array.

13.

Which one of these lists contains only Java programming language keywords?

A.	class, if, void, long, Int, continue
B.	goto, instanceof, native, finally, default, throws
C.	try, virtual, throw, final, volatile, transient
D.	strictfp, constant, super, implements, do
E.	byte, break, assert, switch, include

Answer: Option B

Explanation:

All the words in option B are among the 49 Java keywords. Although goto reserved as a keyword in Java, goto is not used and has no function.

Option A is wrong because the keyword for the primitive int starts with a lowercase i.

Option C is wrong because "virtual" is a keyword in C++, but not Java.

Option D is wrong because "constant" is not a keyword. Constants in Java are marked static and final.

Option E is wrong because "include" is a keyword in C, but not in Java.

14.

Which four options describe the correct default values for array elements of the types indicated?

1 int -> 0

2 String -> "null"

3 Dog -> null

4 char -> '\u0000'

5 float -> 0.0f

6 boolean -> true

A.	1, 2, 3, 4
B.	1, 3, 4, 5
C.	2, 4, 5, 6
D.	3, 4, 5, 6

Answer: Option B

Explanation:

(1), (3), (4), (5) are the correct statements.

(2) is wrong because the default value for a String (and any other object reference) is null, with no quotes.

(6) is wrong because the default value for boolean elements is false.

Language Fundamentals - General Questions (2)

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