How to Maximize the Window Size in Selenium Java?

To maximize the window size in Selenium Java, the standard and most straightforward approach is to use the maximize() method from the WebDriver.Window interface. This method expands the browser window to occupy the maximum available screen space. Maximizing the window at the start of your test scripts is considered best practice to ensure Selenium can properly interact with all elements on the page, reducing the chances of missing elements that may otherwise be out of view in a smaller window.

Example Code

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;

public class MaximizeWindowExample {
    public static void main(String[] args) {
        // Initialize the driver (uncomment and set path if ChromeDriver isn't on your PATH)
        // System.setProperty("webdriver.chrome.driver", "path/to/chromedriver");
        WebDriver driver = new ChromeDriver();

        // Navigate to your desired URL
        driver.get("https://www.example.com");

        // Maximize the current window
        driver.manage().window().maximize();

        // Optional: Pause to visually confirm maximization (remove in production)
        try { Thread.sleep(5000); } catch (InterruptedException e) { }

        // Close the browser
        driver.quit();
    }
}

How it works:

• driver.manage().window().maximize(); resizes the browser to the full available screen.

Alternative Approach for Chrome

You can also launch Chrome in maximized mode using ChromeOptions:

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.chrome.ChromeOptions;

ChromeOptions options = new ChromeOptions();
options.addArguments("--start-maximized");
WebDriver driver = new ChromeDriver(options);

When to Use

• Maximizing the browser is crucial for robust UI testing and is generally done immediately after opening the browser and before beginning interactions.

This ensures your automation scripts have the best chance of interacting with all visible elements, regardless of the user’s display settings or default browser window size.