我testng用来运行我编写的测试用例，Java但由于给出此错误而失败。
由于缺乏开发知识，我无法找出以下错误的确切根本原因：
[2013-11-11 08:31:57,401] 错误 PoolService-0 com.zycus.testautomation.common.Utility afterExecutionOfTestcase - 注销失败 =>java.lang.NullPointerException：条目中的空值：url = null [java] java。 lang.NullPointerException：条目中的空值：com.google.common.base.Preconditions.checkNotNull（Preconditions.java:235）的 url = null [java] [java] com.google.common.collect.ImmutableBiMap.of（ ImmutableBiMap.java:61) [java] at com.google.common.collect.ImmutableMap.of(ImmutableMap.java:80) [java] at org.openqa.selenium.remote.RemoteWebDriver.get(RemoteWebDriver.java:276) [java] 在 com.zycus.testautomation.common.LoginLogoutUtil.iAnalyzeLogout(LoginLogoutUtil.java:92) [java] 在 com.zycus.testautomation.common.Utility.afterExecutionOfTestcase(Utility.java:第1256章、 .invoke(Unknown Source) [java] at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) [java] at java.lang.reflect.Method.invoke(Unknown Source) [java] at org.testng.internal.MethodInvocationHelper。 invokeMethod(MethodInvocationHelper.java:80) [java] at org.testng.internal.Invoker.invokeMethod(Invoker.java:714) [java] at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:901) [java ] 在 org.testng.internal.TestMethodWithDataProviderMethodWorker.call(TestMethodWithDataProviderMethodWorker.java:73) [java] at org.testng.internal.TestMethodWithDataProviderMethodWorker.call(TestMethodWithDataProviderMethodWorker.java:14) [java] at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) [java] at java.util.concurrent .FutureTask.run(Unknown Source) [java] at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [java] at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) [java] at java.util.concurrent.FutureTask.run(Unknown Source) [java] at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source) [java] at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source ) [java] 在 java.lang.Thread.run(Unknown Source)call(TestMethodWithDataProviderMethodWorker.java:14) [java] at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) [java] at java.util.concurrent.FutureTask.run(Unknown Source) [java] at java. util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [java] at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) [java] at java.util.concurrent.FutureTask.run(Unknown Source) [ java] at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source) [java] at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [java] at java.lang.Thread.run(Unknown资源）call(TestMethodWithDataProviderMethodWorker.java:14) [java] at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) [java] at java.util.concurrent.FutureTask.run(Unknown Source) [java] at java. util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [java] at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) [java] at java.util.concurrent.FutureTask.run(Unknown Source) [ java] at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source) [java] at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [java] at java.lang.Thread.run(Unknown资源）FutureTask.run(Unknown Source) [java] at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [java] at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) [java] at java .util.concurrent.FutureTask.run(Unknown Source) [java] at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source) [java] at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [java] 在 java.lang.Thread.run（未知来源）FutureTask.run(Unknown Source) [java] at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [java] at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) [java] at java .util.concurrent.FutureTask.run(Unknown Source) [java] at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source) [java] at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [java] 在 java.lang.Thread.run（未知来源）runTask(Unknown Source) [java] at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [java] at java.lang.Thread.run(Unknown Source)runTask(Unknown Source) [java] at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [java] at java.lang.Thread.run(Unknown Source)
一点帮助将不胜感激，在此先感谢