39. Multi-Threaded Parallel Execution with ThreadLocal WebDriver

ThreadLocal WebDriver Pattern

WebDriver is not thread-safe. If two parallel test threads share the same driver variable, they overwrite each other's commands and crash. ThreadLocal<WebDriver> ensures each thread has its own isolated instance:

public class DriverManager {
    private static final ThreadLocal<WebDriver> driverThread = new ThreadLocal<>();
public static WebDriver getDriver() {
        return driverThread.get();
    }
public static void setDriver(WebDriver driver) {
        driverThread.set(driver);
    }
public static void quitDriver() {
        if (driverThread.get() != null) {
            driverThread.get().quit();
            driverThread.remove(); // Prevent memory leaks
        }
    }
}