How to change window selenium java?

I'm trying to access iframe inside html tag.xpath is not working.How to change my window to iframe in selenium(java/maven)?

First you need to create driver object and after you can switch windows by id, name and WebElement.Then driver object has functions for switch back to default window.like this example.

// create driver object
WebDriver driver = DriverManager.getDriver();

// change window using iframe id or iframe name
driver.switchTo().frame("frame id or frame name");

// change window using WebElement object
driver.switchTo().frame(webElement);

Switch back window

// switch back to main frame
driver.switchTo().parentFrame();
// switch back one frame
driver.switchTo().defaultContent();

> Content copy from (read this article) selenium window change article.Impotent information's here.

1. Right Click on HTML Page the search there for iframe.
2. Get the frame ID, Name or index.
3. pass one of the above parameters into following command

   driver.switchTo.Frame(" ID or Name Or index");
   

4. then try to use your xpath.

You can use: deiver.switchTo Method with the element locator, you can find more with the following: https://www.guru99.com/handling-iframes-selenium.html

Basically, the question is to change window we have java inbuild methods.

1. get.windowhandle(): This method helps to get the window handle of the current window

2. get.windowhandles():This method helps to get the handles of all the windows opened. It stores all the current active windows into set..
so if you get all the window handle you can do is example:

code:
Set<String> setLink = driver.get.windowhandles();
now you can simply do the indexing and switch.
ex.
driver.get(setLink[2]);

3. Another method to switch is using keyBoardkeys
     String clickl = Keys.chord(Keys.CONTROL,Keys.TAB);

     String clickl = Keys.chord(Keys.CONTROL,Keys.(Index of window you like 1,2,3));

      // open the link in new tab, Keys.Chord string passed to sendKeys
      driver.findElement(
      By.xpath("any xpath")).sendKeys(clickl);