Opening the chrome driver and browser on a specific port, and connecting to already opened chrome browser.

Introduction:

This article helps you in understanding how to start chrome driver on a specific port, connect to an existing browser session and opening chrome browser with debug port opened through selenium scripts.

You should use ChromeDriverService for starting chrome in a different port:

import org.openqa.selenium.chrome.WebDriver;
      import org.openqa.selenium.chrome.ChromeDriverService;
      import org.openqa.selenium.chrome.ChromeOptions;
      import org.openqa.selenium.remote.RemoteWebDriver;     

      WebDriver browser = null;
  	  ChromeDriverService service = new ChromeDriverService.Builder()
      .usingDriverExecutable(new File("C:\\chromedriver.exe"))
      .usingPort(4444) 
      .build();
  	  service.start(); 
  	  browser = new RemoteWebDriver(service.getUrl(), new ChromeOptions());

Once your tests are done, make sure to close the browser and the service:

browser.quit()
  service.stop()

Else the port remains open.

Output:

Add alt text

Connecting to an existing chrome browser from selenium:

close all chrome browsers and then, start the Chrome browser in debug mode by opening cmd and running chrome.exe with — remote-debugging-port argument

"<path>\chrome.exe" --remote-debugging-port=1559

Now open any other browser and navigate to localhost:1559 to check that the browser was indeed opened with that port

Now in selenium code use chrome experimental option to connect to this chrome option

System.setProperty("webdriver.chrome.driver", "C:\\chromedriver.exe");
    ChromeOptions options = new ChromeOptions();
    options.setExperimentalOption("debuggerAddress", "127.0.0.1:1557");
    WebDriver browser=new ChromeDriver(options);

Running Chrome on specific debug port from selenium:

System.setProperty("webdriver.chrome.driver", "C:\\chromedriver.exe");
    ChromeOptions options = new ChromeOptions();
    options.addArguments("--remote-debugging-port=1557");
    WebDriver browser = new ChromeDriver(options);
    options.setExperimentalOption("debuggerAddress", "127.0.0.1:1557");
    browser=new ChromeDriver(options);

Output: