how to send JSON to a REST web service -

i wrote simple web service in mailrest class path:

@path("/service") 

the post method want test is:

@post @path("/sendtest/") @consumes(mediatype.application_json) @produces(mediatype.text_plain) public string test(jsonobject json) {      string input = (string) json.get("input");     string output = "the input sent is:" + input;     system.err.println(output);      return "hello"; } 

my mailrestclient class is:

static final string rest_uri = "http://localhost:9999/mail"; static final string mail = "service/sendtest";  public static void main(string[] args) {      mail mail = new mail();     mail.setfrom("testfrom");     mail.setto("testto");      byte[] attachment = new byte[] {};     string attachmentbase64encoded = datatypeconverter.printbase64binary(attachment);      gson g = new gson();     string json = g.tojson(mail);      ?????  } 

i understand best method calling

i saw examples apache httpclient , jersey, i'm unable make them work.