Appium测试项目异常Returned value cannot be converted to WebElement: {ELEMENT=1}

[TestNG] Running:
  C:\Users\AppData\Local\Temp\testng-eclipse--462043372\testng-customsuite.xml
FAILED: plus
org.openqa.selenium.WebDriverException: Returned value cannot be converted to WebElement: {ELEMENT=1}
Build info: version: '2.53.1', revision: 'a36b8b1', time: '2016-06-30 17:32:46'
System info: host: 'dongao-PC', ip: '172.16.203.52', os.name: 'Windows 7', os.arch: 'amd64', os.version: '6.1', java.version: '1.8.0_91'
Driver info: driver.version: AndroidDriver
    at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:370)
    at io.appium.java_client.DefaultGenericMobileDriver.findElement(DefaultGenericMobileDriver.java:62)
    at io.appium.java_client.AppiumDriver.findElement(AppiumDriver.java:1)
    at io.appium.java_client.android.AndroidDriver.findElement(AndroidDriver.java:1)
    at org.openqa.selenium.remote.RemoteWebDriver.findElementById(RemoteWebDriver.java:413)
    at io.appium.java_client.DefaultGenericMobileDriver.findElementById(DefaultGenericMobileDriver.java:70)
    at io.appium.java_client.AppiumDriver.findElementById(AppiumDriver.java:1)
    at io.appium.java_client.android.AndroidDriver.findElementById(AndroidDriver.java:1)
    at com.dongao.autoapptest.cc1.test.CaculatorTest.plus(CaculatorTest.java:38)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:104)
    at org.testng.internal.Invoker.invokeMethod(Invoker.java:645)
    at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:851)
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1177)
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:129)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:112)
    at org.testng.TestRunner.privateRun(TestRunner.java:756)
    at org.testng.TestRunner.run(TestRunner.java:610)
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:387)
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:382)
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:340)
    at org.testng.SuiteRunner.run(SuiteRunner.java:289)
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1293)
    at org.testng.TestNG.runSuitesLocally(TestNG.java:1218)
    at org.testng.TestNG.runSuites(TestNG.java:1133)
    at org.testng.TestNG.run(TestNG.java:1104)
    at org.testng.remote.AbstractRemoteTestNG.run(AbstractRemoteTestNG.java:132)
    at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:236)
    at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:81)
Caused by: java.lang.ClassCastException: java.util.HashMap cannot be cast to org.openqa.selenium.WebElement
    at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:368)
    ... 33 more


===============================================
    Default test
    Tests run: 1, Failures: 1, Skips: 0
===============================================


===============================================
Default suite
Total tests run: 1, Failures: 1, Skips: 0
===============================================

[TestNG] Time taken by org.testng.reporters.EmailableReporter2@15aab8c6: 13 ms
[TestNG] Time taken by org.testng.reporters.JUnitReportReporter@6babf3bf: 16 ms
[TestNG] Time taken by [FailedReporter passed=0 failed=0 skipped=0]: 15 ms
[TestNG] Time taken by org.testng.reporters.XMLReporter@3d5c822d: 41 ms
[TestNG] Time taken by org.testng.reporters.jq.Main@2f217633: 78 ms

[TestNG] Time taken by org.testng.reporters.SuiteHTMLReporter@5acf93bb: 109 ms

出现上述错误，就是因为appium的java-client版本和selenium-server-standalone版本不匹配，我将两个版本都升级到最新，问题就解决了

java-client-5.0.4.jar

selenium-server-standalone-3.8.1.jar