java.lang.NoSuchMethodError: org.springframework.http.MediaType.getCharset()Ljava/nio/charset/Charset

Question

When I attempt to run my TestNG tests via ant I am getting java.lang.NoSuchMethodError: org.springframework.http.MediaType.getCharset()Ljava/nio/charset/Charset (see below for full exception)

I have no trouble compiling or running my web application but can't run tests via ant. I'm fairly certain this is a class loading issue but not sure what order class loading should be done at runtime. I'm using Spring 4.3.1 and Spring Security 4.1.1.

Is there a particular order to load my jars such that the "correct" version of org.springframework.http.MediaType is used?

[testng] org.testng.TestNGException: 
   [testng] An error occurred while instantiating class com.avada.rest.api.GroupsIntTest: org.springframework.http.MediaType.getCharset()Ljava/nio/charset/Charset;
   [testng]     at org.testng.internal.ClassHelper.createInstance1(ClassHelper.java:388)
   [testng]     at org.testng.internal.ClassHelper.createInstance(ClassHelper.java:290)
   [testng]     at org.testng.internal.ClassImpl.getDefaultInstance(ClassImpl.java:125)
   [testng]     at org.testng.internal.ClassImpl.getInstances(ClassImpl.java:191)
   [testng]     at org.testng.TestClass.getInstances(TestClass.java:104)
   [testng]     at org.testng.TestClass.initTestClassesAndInstances(TestClass.java:90)
   [testng]     at org.testng.TestClass.init(TestClass.java:82)
   [testng]     at org.testng.TestClass.<init>(TestClass.java:45)
   [testng]     at org.testng.TestRunner.initMethods(TestRunner.java:409)
   [testng]     at org.testng.TestRunner.init(TestRunner.java:247)
   [testng]     at org.testng.TestRunner.init(TestRunner.java:217)
   [testng]     at org.testng.TestRunner.<init>(TestRunner.java:161)
   [testng]     at org.testng.SuiteRunner$DefaultTestRunnerFactory.newTestRunner(SuiteRunner.java:555)
   [testng]     at org.testng.SuiteRunner.init(SuiteRunner.java:168)
   [testng]     at org.testng.SuiteRunner.<init>(SuiteRunner.java:117)
   [testng]     at org.testng.TestNG.createSuiteRunner(TestNG.java:1359)
   [testng]     at org.testng.TestNG.createSuiteRunners(TestNG.java:1346)
   [testng]     at org.testng.TestNG.runSuitesLocally(TestNG.java:1200)
   [testng]     at org.testng.TestNG.runSuites(TestNG.java:1124)
   [testng]     at org.testng.TestNG.run(TestNG.java:1096)
   [testng]     at org.testng.TestNG.privateMain(TestNG.java:1425)
   [testng]     at org.testng.TestNG.main(TestNG.java:1394)
   [testng] Caused by: java.lang.NoSuchMethodError: org.springframework.http.MediaType.getCharset()Ljava/nio/charset/Charset;
   [testng]     at org.springframework.web.client.RestTemplate$AcceptHeaderRequestCallback.getSupportedMediaTypes(RestTemplate.java:757)
   [testng]     at org.springframework.web.client.RestTemplate$AcceptHeaderRequestCallback.doWithRequest(RestTemplate.java:733)
   [testng]     at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:617)
   [testng]     at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:580)
   [testng]     at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:287)
   [testng]     at com.avada.rest.api.ApiTestClient.getAll(ApiTestClient.java:81)
   [testng]     at com.avada.rest.api.GroupsIntTest.<clinit>(GroupsIntTest.java:17)
   [testng]     at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
   [testng]     at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
   [testng]     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
   [testng]     at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
   [testng]     at org.testng.internal.ObjectFactoryImpl.newInstance(ObjectFactoryImpl.java:29)
   [testng]     at org.testng.internal.ClassHelper.createInstance1(ClassHelper.java:377)
   [testng]     ... 21 more
   [testng] The tests failed.

Answer 1

Unbelievable...foiled by class loading issues once again...an uber jar named activemq-minimal-5.13.3.jar had references to spring jars in it that was causing the conflict. activemq-minimal-5.13.3.jar comes before spring alphabetically so the classes in that activemq jar were being loaded/used over the spring jars. Updated my ant build to load the spring classes first and now I'm all set.

The way I found out is I put all of my 3rd party libs together in a "Test" project and added/deleted jars (with somewhat of an inclination where the problem was) until I was able to pinpoint where the class loading issue was.