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Questions on Declaration and Access Control
- Given a one dimensional array arr, what is the correct way of
getting the number of elements in arr. Select the one correct answer.
- arr.length
- arr.length - 1
- arr.size
- arr.size - 1
- arr.length()
- arr.length() - 1
- Which of these statements are legal. Select all correct answers.
- int arr[][] = new int[5][5];
- int []arr[] = new int[5][5];
- int[][] arr = new int[5][5];
- int[] arr = new int[5][];
- int[] arr = new int[][5];
- Write the expression to access the number of elements in a one
dimensional array arr. The expression should not be assigned to any
variable.
- Which of these array declarations and initializations are legal?
Select all correct answers.
- int arr[4] = new int[4];
- int[4] arr = new int[4];
- int arr[] = new int[4];
- int arr[] = new int[4][4];
- int[] arr = new int[4];
- What will the result of compiling and executing the following
program. Select the one correct answer.
class Test {
public static void main(String args[]) {
int arr[] = new int[2];
System.out.println(arr[0]);
}
}
- The program does not compile because arr[0] is being read before
being initialized.
- The program generates a runtime exception because arr[0] is being
read before being initialized.
- The program compiles and prints 0 when executed.
- The program compiles and prints 1 when executed.
- The program compiles and runs but the results are not predictable
because of un-initialized memory being read.
- Which of the following are legal declaration and definition of a
method. Select all correct answers.
- void method() {};
- void method(void) {};
- method() {};
- method(void) {};
- void method {};
- Which of the following are valid constructors within a class Test.
Select all correct answers.
- test() { }
- Test() { }
- void Test() { }
- private final Test() { }
- abstract Test() { }
- Test(Test t) { }
- Test(void) { }
- What is the result of compiling and running the following class.
Select the one correct answer.
class Test {
public void methodA(int i) {
System.out.println(i);
}
public int methodA(int i) {
System.out.println(i+1);
return i+1;
}
public static void main(String args[]) {
Test X = new Test();
X.methodA(5);
}
}
Select the one correct answer.
- The program compiles and runs printing 5.
- The program compiles and runs printing 6.
- The program gives runtime exception because it does not find the
method Test.methodA(int)
- The program give compilation error because methodA is defined
twice in class Test.
Answers to questions on
Declarations
- a
- a, b, c
- arr.length
- c, e. The size of the array should not be specified when declaring
the array.
- c
- a
- b, f. A constructor must have the same name as the class, hence a is
not a constructor. It must not return any value, hence c is not correct.
A constructor cannot be declared abstract or final.
- d
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