How to Work with Java Data Types in Automation

Last updated on November 28th, 2025 at 05:26 am

Understanding Java data types is an important step for anyone learning Java or starting with Selenium WebDriver automation. In this Java data types tutorial, you will learn what data types in Java are, how they work, and how to use them in real test automation scenarios. Since data types decide the kind of values a program can store, they are an important part of writing clean and error-free code.

In Java, data types define what type of value a variable can store and how much memory is allocated. Java provides different primitive data types like byte, short, int, long, float, double, char, and boolean. You will use several of these primitive data types in real Selenium test cases. Some types like int, double, char, and boolean are used frequently, while types like byte and short are used rarely.

Below is a simple and complete guide that explains the most commonly used Java primitive data types and the String class with examples.

• What Are Data Types in Java
• Primitive Data Types in Java
  • byte Data Type
  • short Data Type
  • int Data Type
  • long Data Type
  • float Data Type
  • double Data Type
  • char Data Type
  • boolean Data Type
• Non Primitive Types in Java
  • Arrays
  • Classes
  • Interfaces
  • Enums
• String Class
• Full Example with All Data Types
• Conclusion

What Are Data Types in Java

Data types in Java define what type of value a variable can store and the range of that value. This helps the compiler understand how much memory to allocate for a variable. Java supports two categories of data types:

• Primitive data types
• Non primitive data types

Primitive data types in Java include values like numbers, decimals, characters, and boolean values. Non primitive types include classes, arrays, and interfaces. Even though String looks like a data type, it is actually a class.

Primitive Data Types in Java

Java provides eight primitive data types. Below are the ones frequently used in automation and basic Java programs.

byte Data Type

The byte data type is useful to store very small integer values. It can store values from negative 128 to positive 127 and takes very little memory.

Example:

byte b = 120;

short Data Type

The short data type is also used to store small integer values, but it can hold a slightly larger range compared to a byte. It stores 16-bit integer values.

Example:

short s = 30000;

int Data Type

The int data type is used to store 32-bit integer values. It cannot store decimal numbers.

Example:

int i = 4523;

long Data Type

The long data type is used to store 64-bit integer values. Use it when the value does not fit inside an int.

Example:

long l = 652345;

float Data Type

The float data type stores 32-bit decimal values. It is useful when you want decimal values but do not need very high precision.

Example:

float f = 45.67f;

double Data Type

The double data type stores 64-bit decimal values. It is used when you need fractional numbers.

Example:

double d1 = 56.2354;
double d2 = 12456;

char Data Type

The char data type stores a single character. It cannot store more than one character.

Example:

char c = 'd';

boolean Data Type

The Boolean data type stores either true or false. It is often used in conditions if you want to check a specific logic.

Example:

boolean b = true;

Non Primitive Types in Java

Here are non primitive data types in Java.

Arrays

An array is used to store multiple values of the same data type in a single variable. It helps you manage test data easily in automation scripts.

Example:

int numbers[] = {10, 20, 30};

Classes

A class is a blueprint for creating objects. In Selenium automation, you will create multiple classes for test cases, page objects, utilities and more.

Example:

class Car {
    String model;
}

Interfaces

An interface contains method declarations without implementation. They are widely used in automation frameworks for defining structure and achieving loose coupling.

Example:

interface Animal {
    void sound();
}

Enums

Enums represent a fixed set of constants. They are useful when you want to define a fixed number of values, like browsers or environment names, in your Selenium framework.

Example:

enum Browser {
    Chrome, Firefox, Edge
}

String Class

String is not a primitive data type. It is a class used to store a group of characters. You will use String values in almost every Selenium WebDriver test script.

Example:

String str = "Hello World";

Learn more about String handling in Java with this detailed

Full Example with All Data Types

Below is a simple Java program that uses different Java data types. You can run this example in Eclipse or any Java editor.

public class DataTypesExample {

    public static void main(String[] args) {

        int i = 4523;
        long l = 652345;
        double d1 = 56.2354;
        double d2 = 12456;
        char c = 'd';
        boolean t = true;
        String str = "Hello World";

        System.out.println("Integer value: " + i);
        System.out.println("Long value: " + l);
        System.out.println("Double d1 value: " + d1);
        System.out.println("Double d2 value: " + d2);
        System.out.println("Char value: " + c);
        System.out.println("Boolean value: " + t);
        System.out.println("String value: " + str);
    }
}

Console Output:

Integer value: 4523
Long value: 652345
Double d1 value: 56.2354
Double d2 value: 12456.0
Char value: d
Boolean value: true
String value: Hello World

Conclusion

Understanding Java data types is an important part of learning Java and writing reliable Selenium WebDriver automation scripts. Each data type in Java stores a specific kind of value, which helps your program run efficiently and without errors. By practising with commonly used types like int, double, char, boolean, and String, you will become more confident in writing clean and readable code. As you continue learning Java, these basics will help you handle advanced concepts more easily and create better automation test cases.

Aravind QA Automation Engineer & Technical Blogger

Aravind is a QA Automation Engineer and technical blogger specializing in Playwright, Selenium, and AI in software testing. He shares practical tutorials to help QA professionals improve their automation skills.

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