Selenium + Jenkins integration: error initializing plugin

Question

I'm running Jenkins 2.289.2 and trying to install Selenium Grid plugin .

When I install the plugin it shows an error on the Loading plugin extentions

I have JDK 8 and 9 on Jenkins.

Here are the logs that I can find from selenium.

/var/jenkins_home/selenium.log

Starting Selenium Grid
[jenkins_home] $ /opt/java/openjdk/bin/java -cp /var/jenkins_home/war/WEB-INF/lib/remoting-4.7.jar hudson.remoting.Launcher -cp /var/jenkins_home/plugins/selenium/WEB-INF/lib/selenium-server-standalone-3.141.59.jar:/var/jenkins_home/plugins/selenium/WEB-INF/lib/htmlunit-driver-standalone-2.33.3.jar -connectTo localhost:35911
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by hudson.remoting.Launcher (file:/var/jenkins_home/war/WEB-INF/lib/remoting-4.7.jar) to method java.net.URLClassLoader.addURL(java.net.URL)
WARNING: Please consider reporting this to the maintainers of hudson.remoting.Launcher
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
Exception in thread "main" java.lang.IllegalArgumentException: object is not an instance of declaring class
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at hudson.remoting.Launcher.addClasspath(Launcher.java:153)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at io.jenkins.remoting.shaded.org.kohsuke.args4j.spi.MethodSetter.addValue(MethodSetter.java:47)
        at io.jenkins.remoting.shaded.org.kohsuke.args4j.spi.StringOptionHandler.parseArguments(StringOptionHandler.java:19)
        at io.jenkins.remoting.shaded.org.kohsuke.args4j.CmdLineParser.parseArgument(CmdLineParser.java:520)
        at hudson.remoting.Launcher.main(Launcher.java:291)

Jenkins Log:

Failed Initializing plugin selenium
java.net.SocketTimeoutException: Accept timed out
   at java.base/java.net.PlainSocketImpl.socketAccept(Native Method)
   at java.base/java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:458)
   at java.base/java.net.ServerSocket.implAccept(ServerSocket.java:565)
   at java.base/java.net.ServerSocket.accept(ServerSocket.java:533)
   at hudson.slaves.Channels.newJVM(Channels.java:227)
   at hudson.plugins.selenium.process.SeleniumProcessUtils.createSeleniumGridVM(SeleniumProcessUtils.java:59)
   at hudson.plugins.selenium.PluginImpl.startHub(PluginImpl.java:176)
   at hudson.plugins.selenium.PluginImpl.postInitialize(PluginImpl.java:136)
   at hudson.PluginManager$2$1$2.run(PluginManager.java:575)
   at org.jvnet.hudson.reactor.TaskGraphBuilder$TaskImpl.run(TaskGraphBuilder.java:169)
   at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:296)
   at jenkins.model.Jenkins$5.runTask(Jenkins.java:1129)
   at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:214)
   at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:117)
   at jenkins.security.ImpersonatingExecutorService$1.run(ImpersonatingExecutorService.java:68)
   at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
   at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
   at java.base/java.lang.Thread.run(Thread.java:829)

After restart Jenkins server on the Manage Plugins page, it appears like that:

Any help?

Answer 1

I had the same problem. Most probably your Jenkins-Instance is running behind a proxy. Go to the plugin-settings page and add your proxy server.