How can selenium web driver get to know when the new window has opened and then resume its execution

Question

I am facing an issue in automating a web application using selenium web driver.

The webpage has a button which when clicked opens a new window. When I use the follow

Answer 1

Below function can wait for given max time until your new window is open

public static void waitForWindow(int max_sec_toWait, int noOfExpectedWindow) {
    FluentWait wait = new FluentWait(driver);
    wait.pollingEvery(Duration.ofMillis(200));
    wait.withTimeout(Duration.ofSeconds(max_sec_toWait));
    wait.ignoring(NoSuchWindowException.class);
    Function function = new Function(){
        @Override
        public Boolean apply(WebDriver driver) {
            Set handel = driver.getWindowHandles();
            if(handel.size() == noOfExpectedWindow) 
                return true;
            else 
                return false;
            }
    };      
    wait.until(function);
}