Unable to find a matching set of capabilities with selenium 3.8.1 and gecko driver 0.19.0

new FirefoxDriver(DesiredCapabilities caps); 

is deprecated, use

FirefoxOptions options = new FirefoxOptions();options.setCapability("marionette", false);WebDriver webDriver = new FirefoxDriver(options);

and you are good to go

Another possible cause is the outdated Firefox version.

I upgraded the version and it works fine!

I could open the browser only setting options.setCapability("marionette", true);, then in the open window I upgraded through the "About Firefox" dialog. Then you have to remove the line about marionette.

Probably the one I had was only going to work with marionette while we are trying to use it with geckodriver, which has a different protocol. Anyone who knows more than me can confirm or deny!

SessionNotCreatedException

SessionNotCreatedException extends WebDriverException and is a RuntimeException which indicates that a session could not be created.

Possible Causes :

The possible causes of a new session not getting created are as follows :

• Compatibility issues between JDK, Selenium, WebDriver and Web Browser versions.
• Accessing the same port number by GeckoDriver or Marionette by the new session which previous session have't released yet.
• Lack of access to CPU
• Lack of Physical Memory
• Lack of Swap Memory
• Lack of Disc Cache
• Lack of Network Bandwidth
• Presence of OS chores within the system.

Code Block :

I don't see any coding issue in your code block as such.

Solution :

The simple solution would be as follows :

• Always use the latest released version of JDK (Java SE 9.0.1), Selenium-Java client (v3.8.1), WebDriver variant (GeckoDriver v0.19.1) and Web Browser (Firefox Quantum Browser).
• If the base version of the Web Browser is too old consider uninstalling the Browser through Revo Uninstaller and install a recent released GA version of Firefox Browser.
• Always use quit() in the tearDown() method so that the webdriver and the webclient both are properly destroyed.
• Clean the Project Workspace from your IDE before and after executing your Test Suite.
• Clear the Browser Cache before and after the execution of your Tests.
• Use CCleaner tool regularly to wipe away the OS chores.
• Execute your Test.