Selenium 2.47 doesn't work with Firefox v31 - selenium

Question

I am using selenium 2.47 with Firefox v31. With this simple implementation:
public void navigateToHomePage() throws Throwable {
System.out.println("Navigate to Home");
driver = new FirefoxDriver();
driver.quit();
}
I got this error:
org.openqa.selenium.WebDriverException: Unable to bind to locking port 7054 within 45000 ms
Build info: version: '2.47.0', revision: '0e4837e', time: '2015-07-29 22:49:49'
System info: host: 'ok-ThinkPad-SL500', ip: '127.0.1.1', os.name: 'Linux', os.arch: 'amd64', os.version: '3.13.0-24-generic', java.version: '1.7.0_79'
Driver info: driver.version: FirefoxDriver
at org.openqa.selenium.internal.SocketLock.lock(SocketLock.java:99)
at org.openqa.selenium.firefox.internal.NewProfileExtensionConnection.start(NewProfileExtensionConnection.java:90)
at org.openqa.selenium.firefox.FirefoxDriver.startClient(FirefoxDriver.java:276)
at org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:116)
at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:223)
at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:216)
at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:212)
at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:125)
at cucumber.features.StepDefinitions.navigateToHomePage(StepDefinitions.java:24)
at ✽.Given I navigate to the home site(/home/ok/workspace/CucumberPOC/src/cucumber/features/UserRegistry.feature:6)
I don't know what is it??

Answer 1

This SocketLock error happens when Firefox tries to bind to port 7054 and fails because another instance already has that port locked.
An immediate solution is make sure you have NO Firefox tasks or process running in the background before launching a new driver. Kill them all and try launching again.
In the long run, you can avoid these issues by creating a new profile, change the port preferences to avoid locks, and then launch the driver using that profile. A short example:
FirefoxProfile profile = new FirefoxProfile();
profile.setPreference(FirefoxProfile.PORT_PREFERENCE, 7046)
driver = new FirefoxDriver(profile);
Unfortunately, when I was looking up the Java terms, I found that this feature was broken in Java's driver once, then it was fixed and then it broke in a later update, so even if you implement the solution I gave you, you may still get these errors in 2.47.
The fix was released in version 2.43.1, so if you don't need the newer versions for another issue/feature, you can try rolling back to a point where you can set a port preference successfully.
Not required reading: Some more technical details of the issue are in this pull request.