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Comparison

Learn ==, !=, <, >, <=, >= operators.

Comparison operators

Comparison operators compare two values and return a boolean (true or false). Java has six:

  • == equal
  • != not equal
  • < less than
  • > greater than
  • <= less or equal
  • >= greater or equal
int age = 18;
System.out.println(age >= 18); // true
System.out.println(age != 18); // false

You can use the results in if conditions.

Practice Print comparison results

Write a Main class with a main method. Assign 10 to int x. Print x == 10 and x < 5 on separate lines with println.

Sample solution

Main.java
public class Main {
    public static void main(String[] args) {
        int x = 10;
        System.out.println(x == 10);
        System.out.println(x < 5);
    }
}

Expected output

true
false

Equality == vs assignment =

In Java == does equality comparison, while = does assignment. They are often confused.

int a = 5;  // assignment: a is set to 5
if (a == 5) // comparison: is a equal to 5?

For Strings, == compares references; to compare content use equals. For numbers, == compares values directly.

Accidentally writing = can give a compile error or a logic bug.

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 Match the operators

Term Meaning
== Equal
!= Not equal
< Less than
>= Greater or equal

2 What is the result of 5 != 3?

  • true Correct answer
  • false
  • 5
  • 3

Explanation: 5 is different from 3, so true.

3 Complete the comparison

Question 
boolean greater = 7 ____ 5;
Answer 
boolean greater = 7 > 5;

Explanation: Greater-than comparison uses >.

All lessons in Beginner

1 Java basics

  1. What is Java?
  2. The main method
  3. Comments
  4. Class skeleton
  5. javac and java
  6. Summary - Java basics

2 Variables

  1. int and double
  2. boolean
  3. String
  4. Naming variables
  5. final variables
  6. Summary - Variables

3 Data types

  1. Primitive types
  2. Type casting
  3. String concatenation
  4. Math class
  5. BigInteger and BigDecimal
  6. Summary - Data types

4 Project: Calculator

  1. Project design
  2. Add/subtract
  3. Multiply/divide
  4. Error handling
  5. Putting it together

5 Operators

  1. Arithmetic
  2. Comparison
  3. Logical
  4. Bitwise
  5. Assignment and increment
  6. Summary - Operators

6 String basics

  1. length and charAt
  2. equals and equalsIgnoreCase
  3. indexOf and substring
  4. toUpperCase and trim
  5. String.format
  6. Summary - String basics

7 Conditionals

  1. The if statement
  2. else and else if
  3. Nested if
  4. switch
  5. Ternary
  6. Summary - Conditionals

8 Loops

  1. The for loop
  2. The while loop
  3. do-while
  4. break and continue
  5. for-each
  6. Summary - Loops

9 Project: Shopping cart

  1. Cart design
  2. Adding items
  3. Calculating totals
  4. Updating quantity
  5. Putting it together

10 Arrays

  1. Declaring arrays
  2. Array access
  3. Filling arrays
  4. Multi-dimensional arrays
  5. Copying arrays
  6. Summary - Arrays

11 Array methods

  1. Arrays.sort
  2. Arrays.toString
  3. Arrays.binarySearch
  4. Arrays.copyOf
  5. Arrays.fill
  6. Summary - Array methods

12 Collections

  1. ArrayList
  2. add and get
  3. HashMap
  4. put and get
  5. HashSet
  6. Summary - Collections

13 Methods

  1. Defining methods
  2. return
  3. void methods
  4. Method overloading
  5. Scope
  6. Summary - Methods

14 Method parameters

  1. Primitive parameters
  2. Object parameters
  3. varargs
  4. Multiple values via array
  5. final parameters
  6. Summary - Method parameters

15 Project: To-do CLI

  1. Task model
  2. Adding tasks
  3. Listing tasks
  4. Completing tasks
  5. Putting it together

16 String builder

  1. StringBuilder
  2. append
  3. insert and delete
  4. reverse
  5. toString
  6. Summary - String builder

17 Input and output

  1. Scanner
  2. nextInt and nextLine
  3. System.out.printf
  4. BufferedReader
  5. try-with-resources
  6. Summary - Input and output

18 Enum

  1. Declaring enums
  2. values and valueOf
  3. Enum fields
  4. Enum methods
  5. switch with enum
  6. Summary - Enum

19 Exception basics

  1. try/catch
  2. finally
  3. throw
  4. Exception hierarchy
  5. Multiple catch
  6. Summary - Exception basics

20 Beginner final

  1. Project design
  2. Data model
  3. Business logic
  4. Error handling
  5. Putting it together