1Z0-811 Primitives, Strings and Operators Practice Test 3 — 15 Questions

Question 1

What is the result of the following code snippet? int a = 5; int b = 2; double c = (double) (a / b); System.out.println(c);

Accepted Answer

2.0. The expression `(a / b)` performs integer division, resulting in 2 (since both a and b are ints). The cast `(double)` is applied to the result of that integer division, converting the integer 2 to 2.0. The output is therefore 2.0.

Answer

2

Answer

Compilation error

Answer

2.5

Question 2

Given: short s = 10; s = s + 5; What is the result?

Accepted Answer

Compilation fails: possible lossy conversion from int to short. The expression `s + 5` performs arithmetic on a `short` and an `int` literal, so the result is promoted to `int`. Assigning that `int` back to a `short` variable without an explicit cast causes a compilation error because an `int` may be larger than a `short` (16-bit range), leading to possible lossy conversion. Therefore, option D is correct.

Answer

s = 10

Answer

Runtime exception

Answer

s = 15

Question 3

What is the output of System.out.println(1 + 2 + "3" + 4 + 5);?

Accepted Answer

3345. Java evaluates the expression left-to-right. The first operation is `1 + 2`, which is integer addition, yielding `3`. Then `3 + "3"` triggers string concatenation, producing `"33"`. The remaining `+ 4` and `+ 5` are also string concatenations, appending `"4"` and `"5"` to give `"3345"`. The `println` method outputs this string.

Answer

12345

Answer

3"3"45

Answer

15

Question 4

Which of the following correctly uses the ternary operator to set int max to the larger of two ints x and y?

Accepted Answer

int max = x > y ? x : y;. The ternary operator `? :` evaluates the boolean expression `x > y`; if true, it returns `x`, otherwise `y`, assigning the larger value to `int max`. This is the standard syntax for a conditional assignment in Java, as defined in the Java Language Specification (JLS §15.25).

Answer

int max = x > y ? y : x;

Answer

int max = if (x > y) x else y;

Answer

int max = (x > y) ? x, y;

Question 5

Given boolean a = true, b = false, c = true; What is the result of (a || b) && (b || c)?

Accepted Answer

true. a||b = true, b||c = true, true && true = true.

Answer

Short-circuit evaluation prevents evaluation

Answer

Compilation error

Answer

false

Question 6

Which primitive type can store a single character?

Accepted Answer

char. char is the primitive for a single 16-bit Unicode character.

Answer

String

Answer

int

Answer

Character

Question 7

What is the output of the following? int x = Integer.MAX_VALUE; x++; System.out.println(x);

Accepted Answer

-2147483648. When x is Integer.MAX_VALUE (2147483647) and incremented, integer overflow occurs because Java int uses 32-bit two's complement representation. The value wraps around to the minimum int value, which is -2147483648, making D correct.

Answer

2147483647

Answer

0

Answer

Exception

Question 8

What is the value of z after executing: int x = 3; int y = 2; int z = x++ * --y;

Accepted Answer

3. The expression `x++ * --y` uses post-increment on `x` and pre-decrement on `y`. Post-increment returns the original value of `x` (3) before incrementing it to 4. Pre-decrement decrements `y` from 2 to 1, then returns the new value (1). The multiplication is 3 * 1 = 3, which is assigned to `z`. So the correct answer is 3.

Answer

6

Answer

4

Answer

2

Question 9

Which TWO of the following are valid declarations and initializations of primitive variables?

Accepted Answer

double d = 10.5;. Options A and C are correct. A: double d = 10.5; is valid because a double literal can be assigned without suffix. C: int i = 10; is valid because 10 fits in an int. B: float f = 10.5; is invalid because 10.5 is a double literal; must use f suffix. D: byte b = 200; is invalid because 200 is out of byte range (-128 to 127). E: long l = 123456789012; is invalid because the literal exceeds int range and lacks L suffix.

Answer

float f = 10.5;

Answer

byte b = 200;

Answer

long l = 123456789012;

Question 10

Which TWO of the following operations on String objects result in a new String object?

Accepted Answer

"Hello".replace('l', 'p'). `String.replace()` returns a new `String` object with the replacement applied, as `String` is immutable in Java. The original `"Hello"` remains unchanged, and a new string `"Heppo"` is created.

Answer

"Hello".toString()

Answer

"Hello".length()

Answer

"Hello".charAt(0)

Question 11

Which THREE of the following statements about operators in Java are true?

Accepted Answer

The instanceof operator can be used to check if an object is an instance of a class.. The `instanceof` operator in Java is a binary operator used to test whether an object is an instance of a specific class, subclass, or interface. It returns `true` if the object is an instance of the specified type, otherwise `false`, and is commonly used for type checking before casting.

Answer

The right shift operator (>>) always fills with zeros.

Answer

The equality operator (==) compares the content of objects.

Question 12

What is the output of the following code?

int x = 5;
int y = 16;
System.out.print(x + "," + y);

Accepted Answer

5,16. The code initializes `int x = 5;` and `int y = 16;` and then prints them using `System.out.print(x + "," + y);`. Since there are no operations that change the values, the output is simply the initial values: 5,16. Therefore, option A is correct.

Answer

4,16

Answer

4,12

Answer

5,12

Question 13

A developer writes: int a = 9; int b = 2; double result = a / b; System.out.println(result); What is the output?

Accepted Answer

4.0. (4.0). In Java, when dividing two integers, the result is integer division, which truncates the fractional part. So 9 / 2 yields 4 (int). This int value is then assigned to a double variable, resulting in 4.0. Option A (4) would be the result of printing an int, but since result is double, it prints 4.0. Option C is incorrect because the code compiles fine. Option D is incorrect because 4.5 would require at least one operand to be double (e.g., a / (double)b).

Answer

4

Answer

Compilation error

Answer

4.5

Question 14

Given: int i = 1; int j = i++ + ++i; What is the value of j?

Accepted Answer

4. The expression `i++ + ++i` is evaluated as follows: First, `i++` uses the current value of i (1) and then increments i to 2. Then, `++i` increments i from 2 to 3 and uses the new value (3). So, j = 1 + 3 = 4. Option A (3) incorrectly assumes both operations use the same initial value. Option B (5) incorrectly increments both times before using. Option C (2) incorrectly uses post-increment for both.

Answer

3

Answer

5

Answer

2