org.openqa.selenium.SessionNotCreatedException: Unable to find a matching set of capabilities with Selenium v3.14.0 and GeckoDriver v0.23.0

Question

My versions are selenium-java-3.14.0 and geckodriver-v0.23.0-win64. I am using the following code.

WebDriver driver;
System.setProperty("webdriver.gecko.driver", "D:\\\\Try out files\\\\geckodriver.exe");
driver = new FirefoxDriver();
String baseURL = "http://www.google.com";
driver.get(baseURL);

When I run it, I get the following error message.

Exception in thread "main" org.openqa.selenium.SessionNotCreatedException: Unable to find a matching set of capabilities
Build info: version: '3.14.0', revision: 'aacccce0', time: '2018-08-02T20:05:20.749Z'
System info: host: '*******', ip: '*****`enter code here`', os.name: 'Windows 10', os.arch: 'amd64', os.version: '10.0', java.version: '1.8.0_151'
Driver info: driver.version: FirefoxDriver
remote stacktrace: 
 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
 at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
 at java.lang.reflect.Constructor.newInstance(Unknown Source)
 at org.openqa.selenium.remote.W3CHandshakeResponse.lambda$new0ドル(W3CHandshakeResponse.java:57)
 at org.openqa.selenium.remote.W3CHandshakeResponse.lambda$getResponseFunction2ドル(W3CHandshakeResponse.java:104)
 at org.openqa.selenium.remote.ProtocolHandshake.lambda$createSession0ドル(ProtocolHandshake.java:122)
 at java.util.stream.ReferencePipeline3ドル1ドル.accept(Unknown Source)
 at java.util.Spliterators$ArraySpliterator.tryAdvance(Unknown Source)
 at java.util.stream.ReferencePipeline.forEachWithCancel(Unknown Source)
 at java.util.stream.AbstractPipeline.copyIntoWithCancel(Unknown Source)
 at java.util.stream.AbstractPipeline.copyInto(Unknown Source)
 at java.util.stream.AbstractPipeline.wrapAndCopyInto(Unknown Source)
 at java.util.stream.FindOps$FindOp.evaluateSequential(Unknown Source)
 at java.util.stream.AbstractPipeline.evaluate(Unknown Source)
 at java.util.stream.ReferencePipeline.findFirst(Unknown Source)
 at org.openqa.selenium.remote.ProtocolHandshake.createSession(ProtocolHandshake.java:125)
 at org.openqa.selenium.remote.ProtocolHandshake.createSession(ProtocolHandshake.java:73)
 at org.openqa.selenium.remote.HttpCommandExecutor.execute(HttpCommandExecutor.java:136)
 at org.openqa.selenium.remote.service.DriverCommandExecutor.execute(DriverCommandExecutor.java:83)
 at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:548)
 at org.openqa.selenium.remote.RemoteWebDriver.startSession(RemoteWebDriver.java:212)
 at org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:130)
 at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:125)
 at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:103)
 at basicweb.FirefoxDriverDemo.main(FirefoxDriverDemo.java:17)

• Guy: Try updating FF browser.

Answer 1

Use firefox version 56 or 61 and gecko driver version 0.21. and add firefox options use profile.

FirefoxOptions fo = new FirefoxOptions();
fo.setBinary("C:\\Users\\ChawlaSh\\AppData\\Local\\Mozilla Firefox\\firefox.exe");
ProfilesIni profile = new ProfilesIni();
FirefoxProfile myprofile = profile.getProfile("default");
fo.setProfile(myprofile);
driver = new FirefoxDriver(fo);

I hope this will surely help.

• undetected Selenium: Any reason to ask OP for downgrading GeckoDriver?
• shubham chawla: I faced same issue month ago and if you check Mozilla release's page on GitHub they have mentioned which gecko driver is compatible with which version of selenium and Firefox for me it worked perfectly.

Answer 2

This error message...

Exception in thread "main" org.openqa.selenium.SessionNotCreatedException: Unable to find a matching set of capabilities

...implies that your program wasn't able to create a new Firefox Browser session..

---

Analysis

There are a couple of issues as follows:

• file.separator: Character that separates components of a file path. This is / on UNIX and \ on Windows. You need to escape them too.
• Your JDK version is 1.8.0_151 which is pretty ancient.

---

Solution

• Use file.separator as \ escaping with another \.
• Upgrade JDK to recent levels JDK 8u191.
• Ensure the GeckoDriver-Firefox Mapping

Geckodriver Releases

• You effective code block will be:

  WebDriver driver;
  System.setProperty("webdriver.gecko.driver", "D:\\Try out files\\geckodriver.exe");
  driver = new FirefoxDriver();
  String baseURL = "http://www.google.com";
  driver.get(baseURL);