This is what I am sending to /openmrs/ws/rest/v1/concept/

{
"answers":
[{"uuid":"0a335152-343d-440b-ac42-00deffcfd5a5"},{"uuid":"49f758e1-4fcf-46e3-b6d9-c2a4f5c3c96b"}],
"names":
[{"name":"Test api 1:", "locale":"ru", "conceptNameType":"FULLY_SPECIFIED"}],
"datatype":"8d4a48b6-c2cc-11de-8d13-0010c6dffd0f",
"conceptClass":"8d491e50-c2cc-11de-8d13-0010c6dffd0f"
}

{
    "error": {
        "message": "[answers on class org.openmrs.Concept]",
        "code": "org.openmrs.module.webservices.rest.web.resource.impl.BaseDelegatingResource:740",
        "detail": "org.openmrs.module.webservices.rest.web.response.ConversionException: answers on class org.openmrs.Concept\r\n\tat org.openmrs.module.webservices.rest.web.resource.impl.BaseDelegatingResource.setProperty(BaseDelegatingResource.java:740)\r\n\tat org.openmrs.module.webservices.rest.web.resource.impl.BaseDelegatingResource.setConvertedProperties(BaseDelegatingResource.java:607)\r\n\tat org.openmrs.module.webservices.rest.web.resource.impl.DelegatingCrudResource.convert(DelegatingCrudResource.java:103)\r\n\tat org.openmrs.module.webservices.rest.web.resource.impl.DelegatingCrudResource.create(DelegatingCrudResource.java:76)\r\n\tat org.openmrs.module.webservices.rest.web.v1_0.controller.MainResourceController.create(MainResourceController.java:92)\r\n\tat sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\r\n\tat sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)\r\n\tat sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\r\n\tat java.lang.reflect.Method.invoke(Method.java:498)\r\n\tat org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:177)\r\n\tat org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:446)\r\n\tat org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:434)\r\n\tat org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943)\r\n\tat org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877)\r\n\tat org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)\r\n\tat org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:868)\r\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:648)\r\n\tat org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)\r\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:729)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)\r\n\tat org.openmrs.module.web.filter.ForcePasswordChangeFilter.doFilter(ForcePasswordChangeFilter.java:60)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)\r\n\tat org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)\r\n\tat org.openmrs.module.web.filter.ModuleFilterChain.doFilter(ModuleFilterChain.java:72)\r\n\tat org.openmrs.web.filter.GZIPFilter.doFilterInternal(GZIPFilter.java:64)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)\r\n\tat org.openmrs.module.web.filter.ModuleFilterChain.doFilter(ModuleFilterChain.java:70)\r\n\tat org.openmrs.module.webservices.rest.web.filter.AuthorizationFilter.doFilter(AuthorizationFilter.java:104)\r\n\tat org.openmrs.module.web.filter.ModuleFilterChain.doFilter(ModuleFilterChain.java:70)\r\n\tat org.springframework.web.filter.ShallowEtagHeaderFilter.doFilterInternal(ShallowEtagHeaderFilter.java:82)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)\r\n\tat org.openmrs.module.web.filter.ModuleFilterChain.doFilter(ModuleFilterChain.java:70)\r\n\tat org.openmrs.module.owa.filter.OwaFilter.doFilter(OwaFilter.java:57)\r\n\tat org.openmrs.module.web.filter.ModuleFilterChain.doFilter(ModuleFilterChain.java:70)\r\n\tat org.openmrs.module.xforms.web.XformsFilter.doFilter(XformsFilter.java:69)\r\n\tat org.openmrs.module.web.filter.ModuleFilterChain.doFilter(ModuleFilterChain.java:70)\r\n\tat org.openmrs.module.web.filter.ModuleFilter.doFilter(ModuleFilter.java:54)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)\r\n\tat org.openmrs.web.filter.OpenmrsFilter.doFilterInternal(OpenmrsFilter.java:108)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)\r\n\tat org.springframework.orm.hibernate4.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:150)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)\r\n\tat org.openmrs.web.filter.StartupFilter.doFilter(StartupFilter.java:105)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)\r\n\tat org.openmrs.web.filter.StartupFilter.doFilter(StartupFilter.java:105)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)\r\n\tat org.openmrs.web.filter.StartupFilter.doFilter(StartupFilter.java:105)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)\r\n\tat org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)\r\n\tat org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)\r\n\tat org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:94)\r\n\tat org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)\r\n\tat org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)\r\n\tat org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)\r\n\tat org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)\r\n\tat org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)\r\n\tat org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:502)\r\n\tat org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1132)\r\n\tat org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:684)\r\n\tat org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2521)\r\n\tat org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2510)\r\n\tat java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)\r\n\tat java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)\r\n\tat org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)\r\n\tat java.lang.Thread.run(Thread.java:748)\r\nCaused by: java.lang.NullPointerException\r\n\tat org.openmrs.module.webservices.rest.web.ConversionUtil.convertMap(ConversionUtil.java:305)\r\n\tat org.openmrs.module.webservices.rest.web.ConversionUtil.convert(ConversionUtil.java:273)\r\n\tat org.openmrs.module.webservices.rest.web.ConversionUtil.convert(ConversionUtil.java:212)\r\n\tat org.openmrs.module.webservices.rest.web.resource.impl.BaseDelegatingResource.setProperty(BaseDelegatingResource.java:726)\r\n\t... 79 more\r\n"
    }
}