BudiBaduQuiziBadu

Java Operators & Expressions Quiz

Java
0 Passed
0% acceptance

40 medium-to-advanced questions Java operators & expressions that force deep thinking about arithmetic, relational, logical, assignment, and ternary operators — including precedence traps, short-circuit behavior, compound assignment quirks, and real-world expression bugs.

40 Questions
~80 minutes
1

Question 1

What is the final value of result after this expression?

java
int a = 5;
int result = a++ + a + ++a * 2 - a--;
A
27
B
28
C
30
D
32
2

Question 2

Why does this code NOT throw a NullPointerException?

java
String s = null;
if (s == null || s.length() > 0) {
    System.out.println("Safe!");
}
A
Short-circuit || skips the second condition when first is true
B
String overrides == to handle null
C
The JVM optimizes null checks
D
It actually does throw NPE
3

Question 3

What is the output of this tricky compound assignment?

java
byte b = 100;
b += 200;
System.out.println(b);
A
44
B
300
C
Compilation error
D
-56
4

Question 4

What is the value of x after this expression?

java
int x = 10;
x = x++ * 2 + --x;
A
38
B
39
C
40
D
Undefined behavior
5

Question 5

Which operator has the HIGHEST precedence?

A
Postfix (x++, x--)
B
Unary (+x, -x, !x)
C
Multiplicative (*, /, %)
D
Additive (+, -)
6

Question 6

What is printed by this bitwise and logical mix?

java
int a = 5;  // binary 101
int b = 3;  // binary 011
System.out.println(a & b);
System.out.println(a | b);
System.out.println(a ^ b);
System.out.println(~a);
A
1\n7\n6\n-6
B
3\n5\n6\n-5
C
1\n7\n6\n-5
D
5\n3\n6\n-6
7

Question 7

What is the output of this short-circuit logic with side effects?

java
boolean x = false;
boolean y = true;
boolean result = x && increment() || y && increment();
System.out.println(result + " " + count);

// Assume: static int count = 0;
static boolean increment() { count++; return true; }
A
true 1
B
true 2
C
false 0
D
true 0
8

Question 8

Which of these expressions requires parentheses to compile?

A
a = b ? c = 10 : d = 20
B
a = b ? c : d = 20
C
a = (b ? c : d) = 20
D
a = b ? c : (d = 20)
9

Question 9

What is the value of z after this complex expression?

java
int x = 8, y = 3;
int z = x++ - --y * 2 + x % y;
A
10
B
11
C
12
D
13
10

Question 10

What is the output of this shift operator puzzle?

java
int x = -8;
System.out.println(x >> 2);
System.out.println(x >>> 2);
A
-2\n1073741822
B
-2\n-2
C
1073741822\n-2
D
-8\n-8
11

Question 11

Why does this compile successfully?

java
short s = 100;
s *= 5;
System.out.println(s);
A
Compound assignment with *= performs automatic cast back to short
B
short can hold 500
C
All arithmetic is done in int
D
It doesn't compile
12

Question 12

What is the result of this nested ternary?

java
int score = 85;
String grade = score >= 90 ? "A" :
              score >= 80 ? "B" :
              score >= 70 ? "C" : "F";
System.out.println(grade);
A
B
B
A
C
C
D
F
13

Question 13

What is printed by this logical vs bitwise comparison?

java
boolean a = true, b = false;
System.out.println(a ^ b);
System.out.println(a & b);
System.out.println(a | b);
A
true\nfalse\ntrue
B
1\n0\n1
C
true\ntrue\ntrue
D
Compilation error
14

Question 14

Which of these expressions will cause a compilation error?

A
int x = 10; x += 5.5;
B
int x = 10; x = x + 5.5;
C
double d = 10; d += 5;
D
float f = 10; f += 5;
15

Question 15

What is the output of this precedence puzzle?

java
System.out.println(5 + 3 * 4 % 2 - 1);
A
4
B
7
C
16
D
6
16

Question 16

What is the value of i after this loop completes?

java
int i = 0;
while (i++ < 5) {
    if (i % 2 == 0) continue;
    System.out.print(i + " ");
}
A
6
B
5
C
7
D
Infinite loop
17

Question 17

What is printed by this deeply nested ternary?

java
int n = 15;
String result = n > 20 ? "High" : n > 10 ? "Medium" : n > 5 ? "Low" : "Very Low";
System.out.println(result);
A
Medium
B
Low
C
High
D
Very Low
18

Question 18

Which statement about operator precedence is FALSE?

A
&& has higher precedence than ||
B
== has higher precedence than &
C
* has higher precedence than +
D
? : has higher precedence than =
19

Question 19

What is the final value of x?

java
int x = 5;
x = x++ + x++ + ++x - --x + x--;
A
30
B
31
C
32
D
Undefined
20

Question 20

What is the output of this expression with multiple assignments?

java
int a, b, c;
a = b = c = 10 + 5;
System.out.println(a + " " + b + " " + c);
A
15 15 15
B
10 5 15
C
15 10 5
D
Compilation error
21

Question 21

Which of these is equivalent to i++?

A
i = i + 1
B
++i
C
i += 1
D
Both A and C
22

Question 22

What is printed?

java
int x = 10;
System.out.println(x > 10 ? "High" : x < 5 ? "Low" : "Medium");
A
Medium
B
High
C
Low
D
Compilation error
23

Question 23

What is the value of b after execution?

java
boolean a = true;
boolean b = !a-- || a++ && false;
A
true
B
false
C
Compilation error
D
Undefined
24

Question 24

Which operator is used for string concatenation?

A
+
B
"+" and "+="
C
++
D
&
25

Question 25

What is the output of this classic precedence trap?

java
System.out.println(10 + 20 + "30" + 40 + 50);
A
30304050
B
1203050
C
1303050
D
100
26

Question 26

What is the final value of counter?

java
int counter = 0;
boolean flag = true;
if (flag = false | increment()) {
    counter++;
}
System.out.println(counter);

static boolean increment() { counter++; return true; }
A
1
B
2
C
0
D
Compilation error
27

Question 27

Which of these expressions has the same value as (a > b) ? a : b?

A
Math.max(a, b)
B
a > b ? a : b
C
Both A and B
D
Neither
28

Question 28

What is printed?

java
int x = 5;
System.out.println(x >>>= 1);
A
2
B
5
C
10
D
0
29

Question 29

Why is it dangerous to use == with floating-point numbers?

A
Because of precision errors in IEEE 754 representation
B
Because floating-point is always exact
C
Because == is not allowed on double
D
Only when using float, not double
30

Question 30

What is the output of this final challenge?

java
int a = 10, b = 20, c = 15;
int result = ++a * 2 + (b-- > c ? --b : ++c) - a++;
System.out.println(result + ", a=" + a + ", b=" + b + ", c=" + c);
A
40, a=12, b=18, c=15
B
41, a=12, b=19, c=15
C
39, a=11, b=18, c=16
D
42, a=12, b=18, c=16
31

Question 31

Which operator has the lowest precedence?

A
? :
B
=
C
||
D
All assignment operators
32

Question 32

What is the result?

java
System.out.println("Result: " + 10 + 20);
A
Result: 1020
B
Result: 30
C
Compilation error
D
Result: 10 20
33

Question 33

Which of these is NOT a valid operator in Java?

A
***
B
instanceof
C
->
D
>>>
34

Question 34

What is the output?

java
int x = 1;
System.out.println(x << 1);
A
2
B
-2
C
1
D
0
35

Question 35

Why should you prefer && and || over & and | when working with boolean expressions?

A
They provide short-circuit evaluation and better performance/safety
B
They are faster to type
C
They work with integers
D
No difference
36

Question 36

What is the value of result?

java
boolean flag = false;
int result = flag ? 100 : 200;
System.out.println(result);
A
200
B
100
C
0
D
Compilation error
37

Question 37

Which assignment is valid without casting?

A
byte b = 100; b = b + 50;
B
byte b = 100; b += 50;
C
Both
D
Neither
38

Question 38

What is printed?

java
System.out.println(5 <= 5 || 10 > 15 && 3 == 4);
A
true
B
false
C
Compilation error
D
0
39

Question 39

What is the most important rule to remember about operator precedence?

A
When in doubt, use parentheses — clarity over cleverness
B
Memorize the full 16-level table
C
All operators have the same precedence
D
Only + and - matter
40

Question 40

After mastering operators, what is the single biggest takeaway for writing robust Java code?

A
Never sacrifice readability for brevity — the JVM doesn’t care about cleverness, but your teammates do
B
Always use the most complex expression possible
C
Operator precedence is unimportant
D
Only use + and = operators

Other Quiz Categories

JavaScript
47 quizzes
Basics
Variables & Data Types
Operators & Expressions
Rust
30 quizzes
Cargo and Project Setup
Variables and Mutability
Data Types
Python
29 quizzes
Introduction & Core Fundamentals
Data Types Overview
Type Casting
Golang
29 quizzes
Basics & Syntax
Data Types & Zero Values
Operators & Expressions
C++
26 quizzes
Basics
Variables & Data Types
Operators & Expression
Matlab
21 quizzes
Basics & Environment
Variables and Data Type
Arrays and Matric
TypeScript
19 quizzes
Introduction and Overview
Installation and Configuration
Basic Types and Type Annotations
SQL Database
15 quizzes
Foundations and Basics
Basic Query Selection
Filter, Sort, and Alias Essentials
PHP
15 quizzes
Syntax Building Blocks
Variable Naming
Data Types Overview
Linked List
11 quizzes
Introduction
Node Structure and Pointer Fundamentals
Singly Linked List

QUIZZES IN Java

1

Java Basics & JVM Fundamentals

50

50 in-depth questions (30 with code) covering Java platform independence, JVM architecture, compilation, bytecode, class loading, memory areas, garbage collection, and your first real Java program.

2

Variables, Data Types & Type Casting

40

40 focused questions Java primitive and reference types, variable declaration rules, widening/narrowing conversions, the final keyword, and the most common type-casting pitfalls.

3

Operators & Expressions

40

40 medium-to-advanced questions Java operators & expressions that force deep thinking about arithmetic, relational, logical, assignment, and ternary operators — including precedence traps, short-circuit behavior, compound assignment quirks, and real-world expression bugs.

4

Strings & String Methods

35

35 in-depth questions covering String immutability, object creation, comparison behavior, common methods, StringBuilder/StringBuffer usage, and performance implications in real-world Java code.

5

Numbers & Math Class

35

35 deep-dive questions on Java's numerical capabilities, from Math utilities and rounding behavior to BigInteger/BigDecimal precision, number formatting, and the subtle dangers of primitive overflow.

6

Arrays & Multi-Dimensional Arrays

35

35 deep and practical questions on Java arrays — from declaration and initialization to advanced 2D/3D usage, Arrays utility methods, common pitfalls, and performance gotchas that trip even senior developers.

7

Classes, Objects & Constructors

40

40 deep and challenging questions that explore every corner of object creation, constructor behavior, the true meaning of this, the subtle differences between instance and static members, and the complete lifecycle of objects in Java.

8

Methods, Parameters & Overloading

35

35 challenging and insight-revealing questions that dive deep into how Java really handles method invocation, parameter passing, overloading resolution, varargs behavior, return type rules, and the subtle edge cases that surprise even experienced developers.

9

Packages & Import Statements

40

40 deep, practical, and often overlooked questions about Java packages — from directory structure enforcement and classpath mechanics to import rules, static imports, naming conventions, and the subtle ways packages affect accessibility, compilation, and runtime behavior.

10

Control Flow (if, else, switch)

35

35 deep, real-world, and frequently misunderstood questions about Java control flow — covering if-else pitfalls, dangling else, fall-through dangers, modern switch expressions, pattern matching, exhaustive checking, and the best practices that prevent bugs in production code.

11

Loops (for, while, do-while)

35

35 deep, practical, and often misunderstood questions about Java loops — from subtle break/continue label behavior and enhanced for-loop limitations to infinite loop detection, do-while quirks, loop unrolling myths, and the performance & safety best practices used in real production systems.

12

Encapsulation & Abstraction in OOP

35

35 in-depth questions (15 with code) covering encapsulation principles, getters/setters implementation, abstraction concepts, abstracting behavior, and design benefits in object-oriented programming.

13

Polymorphism (Compile-Time & Runtime)

35

35 in-depth questions (15 with code) covering method overloading as compile-time polymorphism, overriding as runtime polymorphism, dynamic method dispatch, upcasting/downcasting, and why polymorphism matters in object-oriented design.

14

Interfaces, Abstract Classes & Multiple Inheritance

35

35 in-depth questions (15 with code) covering interface basics, abstract class fundamentals, default/static methods in interfaces, functional interfaces, and multiple inheritance resolution in Java.

15

Exception Handling (try, catch, finally)

40

40 in-depth questions (20 with code) covering types of exceptions, try/catch syntax, finally block purpose, stack traces, and best practices in Java exception handling.

16

Custom Exceptions & Exception Hierarchy

30

30 in-depth questions (15 with code) covering creating custom exceptions, throw vs throws, checked vs unchecked exceptions, chained exceptions, and designing exception structures in Java.

17

Collections Framework (List, Set, Map)

35

35 in-depth questions (18 with code) covering List types (ArrayList, LinkedList), Set types (HashSet, TreeSet), Map types (HashMap, TreeMap), Collections utility class, and choosing the right collection for different use cases in Java.

18

Generics Deep Dive

35

35 in-depth questions (18 with code) covering why generics exist, generic methods, bounded type parameters, wildcards (? extends, ? super), and raw types pitfalls in Java.

19

Java I/O (Files, Streams, Readers/Writers)

35

35 in-depth questions (18 with code) covering Input/Output streams, Readers vs Writers, File operations, Buffered I/O, and handling I/O exceptions in Java.

20

Date & Time API (java.time)

35

35 in-depth questions (18 with code) covering LocalDate & LocalTime, LocalDateTime & ZonedDateTime, formatting dates, parsing dates, and Duration & Period in Java's modern date-time API.

21

Streams API (map, filter, reduce)

35

Master the Java Streams API for functional-style operations on collections. Learn to create streams, use intermediate operations like map and filter, apply terminal operations, perform reductions, and follow best practices for efficient stream processing.

22

JVM Memory Model (Heap, Stack, GC)

40

Understand the JVM memory architecture including heap and stack management, garbage collection mechanisms, classloader hierarchy, memory leak prevention, and JVM optimization techniques.