gistfile1.java

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import com.orientechnologies.orient.core.db.document.ODatabaseDocumentTx;

public class TestCloseConnection {

  /**
	 * @param args
	 * @throws InterruptedException
	 */
	public static void main(String[] args) throws InterruptedException {

		ExecutorService executor = Executors.newFixedThreadPool(20);
		for (int i = 0; i < 30000; i++) {
			MyRunnable runnable = new MyRunnable(i);
			executor.execute(runnable);
		}
		// This will make the executor accept no new threads
		// and finish all existing threads in the queue
		executor.shutdown();

		Thread.sleep(60000);

	}

	static class MyRunnable implements Runnable {

		private int id;

		public MyRunnable(int id) {
			this.id = id;
		}

		@Override
		public void run() {
			ODatabaseDocumentTx conn = null;
			try {
				conn = new ODatabaseDocumentTx("remote:localhost/mydb").open("admin", "admin");
				System.out.println("Opened " + id + " connection " + conn);
				
				// do stuff
			} finally {
				conn.close();
				System.out.println("Closed " + id + " connection");
			}

		}
	}
}

Yes I got absolutely the same one )