D286 Java Fundamentals - Set 3 - Part 1

Correct Answer: 5

Post-increment prints the current value 5 first, then increments x to 6. The increment happens after the value is used in the expression.

Correct Answer: 6

Pre-increment increases x to 6 before the value is used, so 6 is printed.

Correct Answer: 20

Multiplication has higher precedence than addition, so 5 * 2 evaluates to 10 first, then 10 + 10 gives 20.

Correct Answer: false

The first operand is true but the second is false. Logical AND requires both to be true, so the result is false.

Correct Answer: "Java"

Strings are immutable, so toUpperCase() returns a new String without modifying s. Since the result is not assigned, s still holds "Java".

Correct Answer: for (int i = 1; i <= 5; i++)

Starting at 1 and continuing while i is less than or equal to 5 produces exactly 1, 2, 3, 4, 5.

Correct Answer: 5

The counter takes the values 0, 2, 4, 6, and 8 before reaching 10 and failing the condition, giving 5 iterations.

Correct Answer: "55"

When one operand of + is a String, the operator performs concatenation, converting the int 5 to "5" and producing "55".

Correct Answer: "105"

Evaluation proceeds left to right: 5 + 5 gives 10, then 10 + "5" concatenates to produce "105".

Correct Answer: int[][] grid = new int[3][4];

The syntax int[][] grid = new int[3][4]; creates a 3-row by 4-column array of integers, all initialized to 0.

Correct Answer: false, because they are different objects in memory

The == operator compares references. Two Strings created with new are distinct objects, so == returns false even when the text is identical.

Correct Answer: Compares content while ignoring capitalization differences

equalsIgnoreCase() compares two Strings character by character while treating uppercase and lowercase letters as equivalent.

Correct Answer: Removes leading and trailing whitespace

trim() returns a new String with leading and trailing whitespace removed, leaving internal spaces intact.

Correct Answer: An array of Strings divided by a delimiter

split() divides a String at each occurrence of the given delimiter or regular expression and returns the resulting pieces as a String array.

Correct Answer: The int value 42

Integer.parseInt() converts a numeric String into its primitive int equivalent, throwing NumberFormatException if the String is not a valid integer.

Correct Answer: 'H'

charAt(0) returns the primitive char at index 0, which is 'H' for the String "Hello".

Correct Answer: Returning the position of the first occurrence of a character or substring

indexOf() returns the index of the first occurrence of the specified character or substring, or -1 if it is not present.

Correct Answer: A boolean indicating whether the substring is present

contains() returns true when the specified character sequence appears within the String, and false otherwise.

Correct Answer: The enhanced for-each loop

The enhanced for loop iterates directly over elements, producing clearer code and eliminating index errors when position is not required.

Correct Answer: add()

ArrayList.add(element) appends the element to the end. An overloaded add(index, element) inserts at a specified position instead.