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Primitive Data Types | Basic Types, Operations
course content

Course Content

Java Basics

Primitive Data TypesPrimitive Data Types

Variables

A variable in code is a kind of cell where we can store information. For example, if we need to save the number 20, we will save it in a variable and use this number again simply by using the variable name in the code.

Java is a strongly typed language, so we are required to define the data type of our variable:

java

Main.java

The code above illustrates the basic syntax for declaring a variable.

Now, let's proceed to the study of data types, beginning with the 8 primary ones.

Data Types

Data type determines the kind of data that will be stored in a container called a variable. There are three types of data: numeric, textual, and boolean. Numeric data types include byte, short, int, long, float, and double. Textual data types are char and String, and boolean data types include boolean.

Note

Note that the String data type is not a primitive data type, so we won't cover it in this section. It has a separate section where you will learn about this data type in detail.

Let's go through primitive data types and learn more about each of them:

  • byte - This integer data type can accept values ranging from -128 to 127. It occupies 1 byte of memory and is stored in the stack memory;
java

Main.java

  • short - is also an integer data type that can hold values ranging from -32,768 to 32,767. It occupies 2 bytes of memory and is stored in the stack memory;
java

Main.java

  • int - This is the most commonly used integer data type, capable of holding values ranging from -2,147,483,648 to 2,147,483,647. It is also stored in the stack memory and occupies 4 bytes;
java

Main.java

  • long - This is the largest integer data type, capable of storing values from -2⁶³ to 2⁶³ - 1. It occupies 8 bytes in memory and is also stored in the stack memory;
java

Main.java

  • float - is the first floating-point data type to store 7 decimal digits. When declaring a variable of type float, we must remember to append the letter f at the end of the number. For example, float myFloat = 4.13f;;
java

Main.java

  • double - This floating-point data type can store up to 15 decimal digits. Unlike float, we don't need to specify letters when declaring a double variable. Double occupies 8 bytes and is stored in the stack memory;
java

Main.java

  • boolean - This primitive data type is special as it can only hold true or false values. Boolean is stored in the stack memory and occupies from 1 bit to 1 byte, depending on the system and compiler;
java

Main.java

  • char - This character data type takes data from the ASCII table. We will delve into this data type in more detail in the next chapter, but for now, please note that it occupies 2 bytes.
java

Main.java

There is also a table where you can view all the essential information about primitive data types:

Data Type Range Size (in bytes) Memory Location
byte -128 to 127 1 Stack
short -32,768 to 32,767 2 Stack
int -2³¹ to 2³¹ - 1 4 Stack
long -2⁶³ to 2⁶³-1 8 Stack
float -2⁻¹⁴⁹ to (2 - 2⁻²³) * 2¹²⁷ 4 Stack
double -2⁻¹⁰⁷⁴ to (2 - 2⁻⁵²) * 2¹⁰²³ 8 Stack
boolean true or false 1 bit to 1 byte Stack
char 0 to 2¹⁶ - 1 2 Stack

Primitive data types can also be output using the console output command. Let's examine some examples:

java

Main.java

We declared an int variable and printed it on the screen.

java

Main.java

We declared a char variable and printed it on the screen.

java

Main.java

We declared a float variable and printed it on the screen.

Note

We don't need to wrap variables in double quotation marks as we did when outputting text using System.out.println().

1. Which integer data type occupies the least amount of memory?
2. What data type can have only two values: ``true`` or ``false``?

Which integer data type occupies the least amount of memory?

Select the correct answer

What data type can have only two values: true or false?

Select the correct answer

Everything was clear?

Section 2. Chapter 1
course content

Course Content

Java Basics

Primitive Data TypesPrimitive Data Types

Variables

A variable in code is a kind of cell where we can store information. For example, if we need to save the number 20, we will save it in a variable and use this number again simply by using the variable name in the code.

Java is a strongly typed language, so we are required to define the data type of our variable:

java

Main.java

The code above illustrates the basic syntax for declaring a variable.

Now, let's proceed to the study of data types, beginning with the 8 primary ones.

Data Types

Data type determines the kind of data that will be stored in a container called a variable. There are three types of data: numeric, textual, and boolean. Numeric data types include byte, short, int, long, float, and double. Textual data types are char and String, and boolean data types include boolean.

Note

Note that the String data type is not a primitive data type, so we won't cover it in this section. It has a separate section where you will learn about this data type in detail.

Let's go through primitive data types and learn more about each of them:

  • byte - This integer data type can accept values ranging from -128 to 127. It occupies 1 byte of memory and is stored in the stack memory;
java

Main.java

  • short - is also an integer data type that can hold values ranging from -32,768 to 32,767. It occupies 2 bytes of memory and is stored in the stack memory;
java

Main.java

  • int - This is the most commonly used integer data type, capable of holding values ranging from -2,147,483,648 to 2,147,483,647. It is also stored in the stack memory and occupies 4 bytes;
java

Main.java

  • long - This is the largest integer data type, capable of storing values from -2⁶³ to 2⁶³ - 1. It occupies 8 bytes in memory and is also stored in the stack memory;
java

Main.java

  • float - is the first floating-point data type to store 7 decimal digits. When declaring a variable of type float, we must remember to append the letter f at the end of the number. For example, float myFloat = 4.13f;;
java

Main.java

  • double - This floating-point data type can store up to 15 decimal digits. Unlike float, we don't need to specify letters when declaring a double variable. Double occupies 8 bytes and is stored in the stack memory;
java

Main.java

  • boolean - This primitive data type is special as it can only hold true or false values. Boolean is stored in the stack memory and occupies from 1 bit to 1 byte, depending on the system and compiler;
java

Main.java

  • char - This character data type takes data from the ASCII table. We will delve into this data type in more detail in the next chapter, but for now, please note that it occupies 2 bytes.
java

Main.java

There is also a table where you can view all the essential information about primitive data types:

Data Type Range Size (in bytes) Memory Location
byte -128 to 127 1 Stack
short -32,768 to 32,767 2 Stack
int -2³¹ to 2³¹ - 1 4 Stack
long -2⁶³ to 2⁶³-1 8 Stack
float -2⁻¹⁴⁹ to (2 - 2⁻²³) * 2¹²⁷ 4 Stack
double -2⁻¹⁰⁷⁴ to (2 - 2⁻⁵²) * 2¹⁰²³ 8 Stack
boolean true or false 1 bit to 1 byte Stack
char 0 to 2¹⁶ - 1 2 Stack

Primitive data types can also be output using the console output command. Let's examine some examples:

java

Main.java

We declared an int variable and printed it on the screen.

java

Main.java

We declared a char variable and printed it on the screen.

java

Main.java

We declared a float variable and printed it on the screen.

Note

We don't need to wrap variables in double quotation marks as we did when outputting text using System.out.println().

1. Which integer data type occupies the least amount of memory?
2. What data type can have only two values: ``true`` or ``false``?

Which integer data type occupies the least amount of memory?

Select the correct answer

What data type can have only two values: true or false?

Select the correct answer

Everything was clear?

Section 2. Chapter 1
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