Introduction

In Java, literals are fixed values that are directly written in the code, such as numbers, characters, or strings. Constants are variables whose values cannot be changed once assigned. Understanding literals and constants is important because they help in writing clear, maintainable, and error-free code. This tutorial explains how to use literals and constants in Java.

---

Code: Literals and Constants Example

public class LiteralsConstantsExample {
// Constant declaration using final keyword
public static final double PI = 3.14159;
public static void main(String[] args) {
// Integer literal
int age = 25;
// Floating-point literal
float height = 5.9f;
// Character literal
char grade = 'A';
// String literal
String name = "John";
// Boolean literal
boolean isJavaFun = true;
// Printing literals and constant
System.out.println("Name: " + name);
System.out.println("Age: " + age);
System.out.println("Height: " + height);
System.out.println("Grade: " + grade);
System.out.println("Is Java fun? " + isJavaFun);
System.out.println("Value of PI: " + PI);
}
}

---

Explanation of Each Code Part

1. Class Declaration

public class LiteralsConstantsExample {

• Defines a Java class named LiteralsConstantsExample.
• public means it can be accessed from anywhere.
• Curly braces {} define the scope of the class.

---

2. Constant Declaration

public static final double PI = 3.14159;

• final: Makes the variable a constant; its value cannot be changed.
• static: Belongs to the class, not an object.
• double: Data type for decimal numbers.
• PI is a constant holding the value of π.

---

3. Main Method

public static void main(String[] args) {

• Entry point of the program.
• JVM executes all code inside this method.
• String[] args allows passing command-line arguments.

---

4. Integer Literal

int age = 25;

• 25 is an integer literal.
• int specifies the data type.
• Stores whole numbers.

---

5. Floating-point Literal

float height = 5.9f;

• 5.9f is a floating-point literal.
• The f denotes a float type.
• Used to store decimal numbers.

---

6. Character Literal

char grade = 'A';

• 'A' is a character literal.
• Stored in a char variable.
• Must be enclosed in single quotes.

---

7. String Literal

String name = "John";

• "John" is a string literal.
• Stored in a String variable.
• Must be enclosed in double quotes.

---

8. Boolean Literal

boolean isJavaFun = true;

• true is a boolean literal.
• Boolean values can be true or false.

---

9. Printing Values

System.out.println("Name: " + name);

• Displays literals and constants on the console.
• + operator concatenates strings with variables.

---

Conclusion

In Java:

• Literals are fixed values written directly in the code.
• Constants are variables declared with final that cannot be changed.
• Using literals and constants improves code readability, prevents accidental changes, and makes programs easier to maintain.

---