"Out of Memory when doing text classification without GUI"

Hi all,

I want to do some text classification tasks out of a self-written Java program using RapidMiner. I already learned a SVN Classification model and stored it to the repository. In my Java application, I read ids out of a database which points to my HDD where the text data is stored. This data is passed to RapidMiner. In order to save memory, the classification task isn't done for all data at once. Instead, I use block sizes. This is basically my application:

public class ApplyModel {

	static String process_definition_file = "apply_model.xml";
	static int num_of_domains = 100000;
	static int block_size = 100; // determines the number of examples classified at once
	static Boolean debug = true;

	public static void main(String[] args) {

		System.out.println("START OF APPLY MODEL");

		try {

			// set RapidMiner confs
			RapidMiner.setExecutionMode(ExecutionMode.COMMAND_LINE);

			int start = 0;
			int iteration = 1;
			while(start < num_of_domains) {

				// init RapidMiner
				RapidMiner.init();

				// read process definition
				Process rm = new Process(new File(process_definition_file));

				// avoid to fetch block size if limit is smaller than block size
				int current_limit = block_size;

				if(num_of_domains < block_size)

					current_limit = num_of_domains;

				// get data
				ImmutableList<RapidMiner2Row> data = [...]

				// transform to ExampleSet
				ExampleSet ex = new CData2ExampleSet().getExampleSet(data);

				// create IO Object
				IOObject ioo = ex;
				IOContainer ioc = new IOContainer(new IOObject[] {ioo});

				// run RapidMiner process
				IOContainer res_ioc = rm.run(ioc);

				// analyze results
				if(res_ioc.getElementAt(0) instanceof ExampleSet) {

					ExampleSet resultSet = (ExampleSet)res_ioc.getElementAt(0);

					// go through results
					for (Example example : resultSet) {

						[...]

					}

				}

				start += current_limit;
				iteration++;

				// clean up
				cdata = null;
				data = null;
				ex = null;
				ioo = null;
				ioc = null;
				rm = null;

			} // end of while

		}

		catch(Exception e) {

			[...]

		}

		System.out.println("END OF APPLY MODEL");

	}

}

Although the RapidMiner process is reinitiated for every data block, i am running into an OutOfMemory Exception (GC overhead limit exceeded). The memory problem depends on the actual amount of data. It only makes a small difference whether I run 100 iterations with 10 data sets or 10 iterations with 100 data sets. Does anyone have an idea?

Regards
Merlot