How to add header to the backend request using java

I'm new with WSO2,I'm trying to add header in the request to my backend, so i done to add it using the calssic method or the xml method as here so now I wanna add it using java method, could you please help me how can make it

Thanks

Within your class mediator, try to get transport header map from axis2 context and add the new one like this.

Map<String, String> headers = (Map) axis2MC.getProperty(
                       org.apache.axis2.context.MessageContext.TRANSPORT_HEADERS);

headers.put("NewHeader", "Value");