[TM4J-users] How to read TM from file,then Add new topic and write it back to file?

[putra l. <jul...@ya...>]

Dear TM4j Users,I am a novice in using TM4J. I want to use Tm4j to store data extractedfrom Email Header. I adapt some methods in "SerialiseTopicMap" and "Tolog"provided in the example of TM4J.When I read emails from mail server,extract information, format them intoTopic Maps  and then write it to disk (in XTM format), I was successfull.Unfortunately, I got problem when I try to read the file containing thatTopic Map for the next use, add some more topics and then write again themodified-Topic-Map into file (the message was"Exception caught: java.lang.NullPointerException").(SEE CODE BELOW)I checked, the problem was not caused by the nullity of variables in thiscode. I do not know what is wrong. Could some of you make suggestion?Thanks in advance. public void run() throws Exception  {    int updated = 0;    PrintStream ps=null;    String f ="c:/TM4J/examples/topicmaps/test.xtm";    try    {      tmps = new mailTM();      if(fileExist(f))      {        System.out.print("Reading file
 "+f+"\n");        tmps.tm= tmps.readTopicMap(f); //THIS METHOD TAKEN FROM TM4J EXAMPLE//TO SEE NUMBER OF ORIGINAL TOPIC IN THE FILE        System.out.print("\nFile "+f+ " LOADED with"+tmps.tm.getTopicCount()+" topics\n");      }      else      {          tmps.createBaseTopic(tmps.tm);          updated=1;      }      Mail ml;      for(int i=arr.begin;i<=arr.end;i++)      {        updated =1;        ml=arr.getEmail();        tmps.makeTopics(tmps.tm,ml); //TO ADD NEW TOPICS TO tmps.tm//TO SEE THAT NEW TOPICS SUCCESSFULLY ADDED        System.out.print("There are "+tmps.tm.getTopicCount()+" topics\n");      }      if(updated==1)      {        ps = new PrintStream(new FileOutputStream(f));//ERROR FOUND IN THIS STATEMENT BELOW, I CHECKED tmps.tm,ps WERE NOT NULLHERE        tmps.writeTopicMap(tmps.tm, ps);      }    }    catch(Exception ex)    {      System.out.println("Exception caught: " + ex.toString());    }  }}


		
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