error for your reference.
Exception in thread "main" java.lang.IllegalArgumentException: Content-Type application/octet-stream is not valid when using multiparts, it must start with "multipart/".
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at org.codehaus.groovy.reflection.CachedConstructor.invoke(CachedConstructor.java:80)
at org.codehaus.groovy.reflection.CachedConstructor.doConstructorInvoke(CachedConstructor.java:74)
at org.codehaus.groovy.runtime.callsite.ConstructorSite$ConstructorSiteNoUnwrap.callConstructor(ConstructorSite.java:84)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallConstructor(CallSiteArray.java:60)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callConstructor(AbstractCallSite.java:235)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callConstructor(AbstractCallSite.java:247)
at com.jayway.restassured.internal.RequestSpecificationImpl.registerRestAssuredEncoders(RequestSpecificationImpl.groovy:1363)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1210)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1019)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:810)
at com.jayway.restassured.internal.RequestSpecificationImpl.invokeMethod(RequestSpecificationImpl.groovy)
at org.codehaus.groovy.runtime.callsite.PogoInterceptableSite.call(PogoInterceptableSite.java:48)
at org.codehaus.groovy.runtime.callsite.PogoInterceptableSite.callCurrent(PogoInterceptableSite.java:58)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:166)
at com.jayway.restassured.internal.RequestSpecificationImpl.sendRequest(RequestSpecificationImpl.groovy:1120)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1210)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1019)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:810)
at com.jayway.restassured.internal.RequestSpecificationImpl.invokeMethod(RequestSpecificationImpl.groovy)
at org.codehaus.groovy.runtime.callsite.PogoInterceptableSite.call(PogoInterceptableSite.java:48)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:149)
at com.jayway.restassured.internal.filter.SendRequestFilter.filter(SendRequestFilter.groovy:30)
at com.jayway.restassured.filter.Filter$filter$0.call(Unknown Source)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
at com.jayway.restassured.filter.Filter$filter.call(Unknown Source)
at com.jayway.restassured.internal.filter.FilterContextImpl.next(FilterContextImpl.groovy:73)
at com.jayway.restassured.filter.time.TimingFilter.filter(TimingFilter.java:56)
at com.jayway.restassured.filter.Filter$filter.call(Unknown Source)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
at com.jayway.restassured.filter.Filter$filter.call(Unknown Source)
at com.jayway.restassured.internal.filter.FilterContextImpl.next(FilterContextImpl.groovy:73)
at com.jayway.restassured.filter.log.RequestLoggingFilter.filter(RequestLoggingFilter.java:101)
at com.jayway.restassured.filter.Filter$filter.call(Unknown Source)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
at com.jayway.restassured.filter.Filter$filter$0.call(Unknown Source)
at com.jayway.restassured.internal.filter.FilterContextImpl.next(FilterContextImpl.groovy:73)
at com.jayway.restassured.filter.FilterContext$next.call(Unknown Source)
at com.jayway.restassured.internal.RequestSpecificationImpl.applyPathParamsAndSendRequest(RequestSpecificationImpl.groovy:1596)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1210)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1019)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:810)
at com.jayway.restassured.internal.RequestSpecificationImpl.invokeMethod(RequestSpecificationImpl.groovy)
at org.codehaus.groovy.runtime.callsite.PogoInterceptableSite.call(PogoInterceptableSite.java:48)
at org.codehaus.groovy.runtime.callsite.PogoInterceptableSite.callCurrent(PogoInterceptableSite.java:58)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallCurrent(CallSiteArray.java:52)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:154)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:182)
at gov.hhs.cms.utils.RestAssuredSample.main(RestAssuredSample.java:30)