Java Programming

I am zipping a large number (about 300,000) of small text files using Java. I am running out of heap space during the operation and I think that this is because the zipping process uses a hashtable which becomes too large. It fails at about 148,000 entries. Here is the code and the error message:

package zippingDriver;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.*;

public class ZipTools {
	
	public static final int BIG_STEP = 1000;
	
	/**
	 * Zips a set of files to the specified directory
	 * 
	 * @param zipPath The path to the zip file that will be created
	 * @param filesToZip An array of file objects that will be added to the zip file
	 * @param directoryName The directory in the zip file to add the files to
	 * @return
	 */
	public static boolean zipFiles(String zipPath, File[] filesToZip, String directoryName) {
		
		System.out.println("zipFiles(" + zipPath + ", " + filesToZip + ", " + directoryName + ")");
		// Create the file
		File zipFile = new File(zipPath);
		try {
			zipFile.createNewFile();
		} catch (IOException e) {
			System.out.println("File already exists.  Will not override the file.");
			e.printStackTrace();
		}
		
		ZipOutputStream zipOut = null;
		
		try {
			zipOut = new ZipOutputStream(new FileOutputStream(zipFile));

			// Set the compression ratio
			zipOut.setLevel(Deflater.DEFAULT_COMPRESSION);

			performZip(zipOut, zipPath, filesToZip, directoryName);

		} catch (FileNotFoundException e) {
			System.out.println("A File was not found (either the zip file or the files to " +
					"place in the zip file).");
			e.printStackTrace();
			return false;
		} catch (IOException e) {
			e.printStackTrace();
		}
		
		
		// Close the ZipOutPutStream
		try {
			zipOut.close();
		} catch (IOException e) {
			e.printStackTrace();
		}

		return true;

	}

	private static void performZip(ZipOutputStream zipOut, String zipPath, 
			File[] filesToZip, String directoryName) throws IOException {
		
		// Create buffer for writing the zip file
		byte[] buffer = new byte[1024];
		
		FileInputStream in = null;
		ZipEntry currentZipEntry;
		
		int length = filesToZip.length;
		int i = 0;
		
		for(i = 0; i < length; i += BIG_STEP) {
			
			int limit = i + BIG_STEP;
			if(limit > length)
				limit = length;
			
			System.out.println(i + "\t" + filesToZip.getName() + " : " + filesToZip[i].getParent());

			

			for(int j = i; j < limit; j++) {

				

				File curr = filesToZip[j];



				//System.out.println(curr.getName() + " : " + curr.getParent());



				// Zip the files inside a subdirectory if necessary

				if(curr.isDirectory()) {

					performZip(zipOut, zipPath, curr.listFiles(), directoryName + File.separator + curr.getName());

					continue;

				}



				// Associate a file input stream for the current file

				in = new FileInputStream(curr);





				// Add ZIP entry to output stream.

				if(directoryName != null)

					currentZipEntry = new ZipEntry(directoryName + File.separator + curr.getName());

				else

					currentZipEntry = new ZipEntry(curr.getName());



				zipOut.putNextEntry(currentZipEntry);



				// Transfer bytes from the current file to the ZIP file

				//out.write(buffer, 0, in.read(buffer));



				int len;

				while ((len = in.read(buffer)) > 0)

				{

					zipOut.write(buffer, 0, len);

				}







				// Close the current entry

				zipOut.closeEntry();



				// Close the current file input stream

				in.close();



				zipOut.flush();

			}

			

			System.gc();

			System.runFinalization();

		}

		

	}

	

}
Error Message:
+Exception in thread "main" java.lang.OutOfMemoryError: Java heap space+
        +at java.util.Hashtable.rehash(Unknown Source)+
        +at java.util.Hashtable.put(Unknown Source)+
        +at java.util.zip.ZipOutputStream.putNextEntry(Unknown Source)+
        +at zippingDriver.ZipTools.performZip(ZipTools.java:107)+
        +at zippingDriver.ZipTools.performZip(ZipTools.java:93)+
        +at zippingDriver.ZipTools.zipFiles(ZipTools.java:42)+
        +at zippingDriver.ZipDriver.main(ZipDriver.java:17)+

Thanks!