public void run() {
                    try {
                        for (int i = 0; i < invokeTimes; i++) {
                            String clientres = (String) server.getRpcServer().invokeSync(
                                remoteAddr, req, 1000);
                            Assert.assertEquals(clientres, RequestBody.DEFAULT_CLIENT_RETURN_STR);
                        }
                    } catch (RemotingException e) {
                        if (e.getMessage().contains("overflow")) {
                            logger.error("overflow exception!");
                            overFlow.add(true);
                        }
                    } catch (InterruptedException e) {
                        String errMsg = "InterruptedException caught in sync!";
                        logger.error(errMsg, e);
                        Assert.fail(errMsg);
                    }

                }
water mark exception test, set a small buffer mark by system property, and trigger write over flow.

@author xiaomin.cxm
@version $Id: WaterMark_SystemProperty_ExceptionTest.java, v 0.1 Apr 6, 2016 8:58:36 PM xiaomin.cxm Exp $
src/test/java/com/alipay/remoting/rpc/watermark/WaterMark_UserProperty_ExceptionTest.java