Programmers have a vast selection of tools at their disposal. The demand for more and better software, applications, and websites is on the rise, so programmers need to bring every helpful resource to bear to promptly create a reliable, excellent product. The need for more products drives the desire for ways to optimize programming for faster outputs, memory, and efficiency.

Today, we're looking at one element of Java programming called literals. This article demystifies literals, exploring what it is, what types exist, and how to use them, offering a few examples, and addressing the most asked questions.

Let’s begin with a definition.

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What Are Literals in Java?

Variables are critical in programming because that’s how you store data in a particular memory location. For example, a Java program, while running, stores values in containers known as “variables,” which are defined as a basic storage unit. To enhance the program’s readability, the programmer must follow particular conventions while naming these variables and assigning values to them. For example, a source code representing a fixed value is "literal.”

Literals in Java are a synthetic representation of boolean, character, numeric, or string data. They are a means of expressing particular values within a program. They are constant values that directly appear in a program and can be assigned now to a variable. For example, here is an integer variable named ‘’/count assigned as an integer value in this statement:

int count = 0;

“int count” is the integer variable, and a literal ‘0’ represents the value of zero.

Therefore, a constant value that is assigned to the variable can be called a literal.

Types of Literals in Java

Literals in Java are typically classified into six types and then into various sub-types. The primary literal types are:

1. Integral Literals

Integral literals consist of digit sequences and are broken down into these sub-types:

  • Decimal Integer: Decimal integers use a base ten and digits ranging from 0 to 9. They can have a negative (-) or a positive (+), but non-digit characters or commas aren’t allowed between characters. Example: 2022, +42, -68.
  • Octal Integer: Octal integers use a base eight and digits ranging from 0 to 7. Octal integers always begin with a “0.” Example: 007, 0295.
  • Hexa-Decimal: Hexa-decimal integers work with a base 16 and use digits from 0 to 9 and the characters of A through F. The characters are case-sensitive and represent a 10 to 15 numerical range. Example: 0xf, 0xe.
  • Binary Integer: Binary integers uses a base two, consisting of the digits “0” and “1.” The prefix “0b” represents the Binary system. Example: 0b11011.

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2. Floating-Point Literals

Floating-point literals are expressed as exponential notations or as decimal fractions. They can represent either a positive or negative value, but if it’s not specified, the value defaults to positive. Floating-point literals come in these formats:

  • Floating: Floating format single precision (4 bytes) end with an “f” or “F.” Example: 4f. Floating format double precision (8 bytes) end with a “d” or “D.”
    Example: 3.14d.
  • Decimal: This format uses 0 through 9 and can have either a suffix or an exponent. Example: 99638.440.
  • Decimal in Exponent form: The exponent form may use an optional sign, such as a "-," and an exponent indicator, such as "e" or "E." Example: 456.5f.

3. Char Literals

Character (Char) literals are expressed as an escape sequence or a character, enclosed in single quote marks, and always a type of character in Java. Char literals are sixteen-bit Unicode characters ranging from 0 to 65535. Example: char ch = 077.

4. String Literals

String literals are sequences of characters enclosed between double quote ("") marks. These characters can be alphanumeric, special characters, blank spaces, etc.

Examples: "John", "2468", "\n", etc.

5. Boolean Literals

Boolean literals have only two values and so are divided into two literals:

  • True represents a real boolean value
  • False represents a false boolean value

So, Boolean literals represent the logical value of either true or false. These values aren't case-sensitive and are equally valid if rendered in uppercase or lowercase mode. Boolean literals can also use the values of “0” and “1.”

Examples:

boolean b = true;

boolean d = false;

6. Null Literals

Null literals represent a null value and refer to no object. Nulls are typically used as a marker to indicate that a reference type object isn’t available. They often describe an uninitialized state in the program. It is a mistake to try to dereference a null value. Example: Patient age = NULL;

Remember, not everyone divides literals in Java into these six types. Alternative classifications split literals into as few as four types (Integer, Character, Boolean, and String) or as many as ten (Integer, Real, Backslash, Character, String, Floating-Point, Boolean, NULL, Class, and Invalid).

How to Use Literals

Programmers who want to incorporate literals in their program begin with the prefix “=,” followed by the specific value.

A Java Literal Example

Here’s a sample of Java programming showing literals:

public class LiteralsExample  

{  

public static void main(String args[])   

{  

int count = 987;  

float floatVal = 4534.99f;  

double cost = 19765.567;  

int hexaVal = 0x7e4;  

int binary = 0b11010;  

char alpha = 'p';  

String str = "Java";  

boolean boolVal = true;  

int octalVal = 067;  

String stuName = null;  

char ch1 = '\u0021';  

char ch2 = 1456;  

System.out.println(count);  

System.out.println(floatVal);  

System.out.println(cost);  

System.out.println(hexaVal);  

System.out.println(binary);  

System.out.println(alpha);  

System.out.println(str);  

System.out.println(boolVal);  

System.out.println(octalVal);  

System.out.println(stuName);  

System.out.println(ch1);  

System.out.println("\t" +"backslash literal");  

System.out.println(ch2);  

}  

}  

Output:

987

4534.99

19765.567

2020

26

p

Java

true

55

null

!

     backslash literal

?

Source 

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Frequently Asked Questions for Literals in Java

1. Can I get a simple, succinct definition of literals in Java?

Sure. Literals are constant values assigned to constant variables. Literals represent fixed values that cannot be modified. Literals are a synthetic representation of boolean, character, numeric, or string data, a medium of expressing particular values in the program.

2. What are literals used for in Java?

Literals are source code representations of a fixed value, represented directly in the code, without any computation.

3. So why should I use literals in Java?

To avoid having to define a constant somewhere and create a label for it. Instead, all you must do is write the value of a constant operand as part of the instructions. Literals are more memory efficient.

4. What are the different data types in Java?

Some basic Java data types include: Floating Point (double), Integer (int), Character (char), and Boolean. Java also uses wrapper classes to support primitive data types. These classes are Byte, Long, Float, Short, Integer, and Double.

5. Can literals in Java ever be changed?

No. Literals consist of immutable characteristics and thus cannot be changed. When programmers create a new variable or a constant, they define a data type and assign particular values. So, when the compiler reads a constant variable's value, it reads and interprets the values as Literals.

6. Why are strings immutable in Java?

Strings are immutable because it is a valuable property for programmers to work with. Immutable objects are easier to reason than their mutable counterparts, and copying the former is fast and easy. Also, immutable objects don't waste memory since the memory isn't changed when the strings are passed around. However, when you pass around mutable objects, their data can be modified by other objects in their path, which eats memory. Hence, choosing immutable objects over mutable ones at every opportunity would be best.

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About the Author

John TerraJohn Terra

John Terra lives in Nashua, New Hampshire and has been writing freelance since 1986. Besides his volume of work in the gaming industry, he has written articles for Inc.Magazine and Computer Shopper, as well as software reviews for ZDNet. More recently, he has done extensive work as a professional blogger. His hobbies include running, gaming, and consuming craft beers. His refrigerator is Wi-Fi compliant.

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