JavaFX - 从JSON数据在HSQLDB中存储数据时的OME

I have used the HSQLDB for storing the data in my app. I make 15 Web service call one by one. and store the data in DB. It's working fine for medimum amount of data. I got the OME(Out of memory error) for large data. I mean, suppose I am having like 20k records for web service method.So we are getting the OME while storing the data into the DB. I tried with profiler feature also but I am unable to find which object was consumed more heap memory. So I struck here. I need the somebody help to solve this.I have used the HSQLDB for storing the data in