import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Types;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class PreparedStatementLeak {
	public static class MyThread extends Thread {
		public MyThread() {
			super();
		}

		private int loop_;

		@Override
		public void run() {

			while (true) {
				try {
					Connection connection;
					connection = DriverManager
							.getConnection("jdbc:apache:commons:dbcp:/jts");
					loop(connection);

					connection.close();
				} catch (SQLException e1) {
					e1.printStackTrace();
				}
			}
		}

		public void loop(Connection connection) {
			PreparedStatement pstmt = null;
			ResultSet rs = null;

			try {
				String sql = "SELECT COUNT(*) * " + (loop_++ % 1000) + " FROM EMP";

				pstmt = connection.prepareStatement(sql);
				rs = pstmt.executeQuery();
				ResultSetMetaData rsmd = rs.getMetaData();

				int columnCount = rsmd.getColumnCount();
				String[] columnNames = new String[columnCount];
				int[] columnTypes = new int[columnCount];
				for (int i = 0; i < columnCount; i++) {
					columnNames[i] = rsmd.getColumnName(i + 1);
					columnTypes[i] = rsmd.getColumnType(i + 1);
				}

				while (rs.next()) {
					for (int i = 0; i < columnNames.length; i++) {
						System.out.println(columnNames[i] + ":" 
									+ rs.getObject(columnNames[i]));
					}
				}
			} catch (SQLException e) {
				e.printStackTrace();
			} finally {
				if (rs != null) {
					try {
						rs.close();
					} catch (SQLException e) {
						e.printStackTrace();
					}
				}
				if (pstmt != null) {
					try {
						pstmt.close();
					} catch (SQLException e) {
						e.printStackTrace();
					}
				}
			}
		}
	}

	public static void main(String[] args) {
		try {
			Class.forName("oracle.jdbc.driver.OracleDriver");
			Class.forName("org.apache.commons.dbcp.PoolingDriver");
		} catch (Exception e) {
			System.out.println(e.getMessage());
			return;
		}

		final int THREADS = 10;
		Thread[] threads = new Thread[THREADS];

		for (int index = 0; index < THREADS; ++index) {
			threads[index] = new MyThread();
			threads[index].start();
		}

		while (true) {
			try {
				Thread.sleep(1000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
}