Testing if the finalize() method is called for objects created by deserialization

FinalizeTester.java

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.net.URL;

import java.net.HttpURLConnection;

/**
 * Testing if the finalize() method is called for objects created by deserialization. 
 * 1 object is instantiated normally 
 * 1 object is deserialized 
 * 2 distinct URLs are opened when the finalize method is called.
 * 
 * You can monitor Tomcat access log on another host: 
 * 192.168.1.2 - - [07/Apr/2016:11:26:09 -0700] "GET /constructed HTTP/1.1" 404 1005
 * 192.168.1.2 - - [07/Apr/2016:11:26:09 -0700] "GET /serialized HTTP/1.1" 404 1003
 *
 * @author Pierre Ernst
 *
 */
public class FinalizeTester {

	private static class MyClass implements Serializable {
		private static final long serialVersionUID = -1286918304474991144L;
		private String url;

		/**
		 * @param url
		 *            monitor this URL to check if/when finalizer is called 
		 */
		public MyClass(String url) {
			this.url = url;
		}

		@Override
		public void finalize() {
			try {
				((HttpURLConnection) new URL(this.url).openConnection()).getResponseCode();
			} catch (IOException ex) {
				// too late
			}
		}
	}

	private static byte[] serialize(Object o) throws IOException {
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		ObjectOutputStream oos = new ObjectOutputStream(baos);
		oos.writeObject(o);
		oos.close();
		baos.close();
		return baos.toByteArray();
	}

	private static Object deserialize(byte[] buffer) throws IOException, ClassNotFoundException {
		ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(buffer));
		Object o = ois.readObject();
		ois.close();
		return o;
	}

	private static String prettyPrintBinary(byte[] buffer) {
		StringBuffer output = new StringBuffer();
		output.append("/* " + ((buffer == null) ? 0 : buffer.length) + " */ byte[] buffer  = new byte[] {");
		if (buffer != null) {
			for (int i = 0; i < buffer.length; i++) {
				if (i > 0) {
					output.append(',');
					if ((i % 10) == 0) {
						// output.append('\n');
					}
				}
				output.append("(byte)0x");
				String hex = Integer.toString((0xFF & buffer[i]), 16).toUpperCase();
				if (hex.length() == 1) {
					output.append('0');
				}
				output.append(hex);
			}
		}
		output.append("};");
		return output.toString();
	}

	public static void main(String... args) {
		try {
			// uncomment to build your own stream
			// System.out.println(prettyPrintBinary(serialize(new MyClass("http://192.168.2.122:666/serialized"))));

			Object o1 = deserialize(new byte[] { (byte) 0xAC, (byte) 0xED, (byte) 0x00, (byte) 0x05, (byte) 0x73,
					(byte) 0x72, (byte) 0x00, (byte) 0x30, (byte) 0x63, (byte) 0x6F, (byte) 0x6D, (byte) 0x2E,
					(byte) 0x73, (byte) 0x61, (byte) 0x6C, (byte) 0x65, (byte) 0x73, (byte) 0x66, (byte) 0x6F,
					(byte) 0x72, (byte) 0x63, (byte) 0x65, (byte) 0x2E, (byte) 0x74, (byte) 0x72, (byte) 0x75,
					(byte) 0x73, (byte) 0x74, (byte) 0x2E, (byte) 0x73, (byte) 0x31, (byte) 0x31, (byte) 0x6E,
					(byte) 0x2E, (byte) 0x46, (byte) 0x69, (byte) 0x6E, (byte) 0x61, (byte) 0x6C, (byte) 0x69,
					(byte) 0x7A, (byte) 0x65, (byte) 0x54, (byte) 0x65, (byte) 0x73, (byte) 0x74, (byte) 0x65,
					(byte) 0x72, (byte) 0x24, (byte) 0x4D, (byte) 0x79, (byte) 0x43, (byte) 0x6C, (byte) 0x61,
					(byte) 0x73, (byte) 0x73, (byte) 0xEE, (byte) 0x23, (byte) 0xF2, (byte) 0x9E, (byte) 0xD6,
					(byte) 0xD1, (byte) 0xF5, (byte) 0xD8, (byte) 0x02, (byte) 0x00, (byte) 0x01, (byte) 0x4C,
					(byte) 0x00, (byte) 0x03, (byte) 0x75, (byte) 0x72, (byte) 0x6C, (byte) 0x74, (byte) 0x00,
					(byte) 0x12, (byte) 0x4C, (byte) 0x6A, (byte) 0x61, (byte) 0x76, (byte) 0x61, (byte) 0x2F,
					(byte) 0x6C, (byte) 0x61, (byte) 0x6E, (byte) 0x67, (byte) 0x2F, (byte) 0x53, (byte) 0x74,
					(byte) 0x72, (byte) 0x69, (byte) 0x6E, (byte) 0x67, (byte) 0x3B, (byte) 0x78, (byte) 0x70,
					(byte) 0x74, (byte) 0x00, (byte) 0x25, (byte) 0x68, (byte) 0x74, (byte) 0x74, (byte) 0x70,
					(byte) 0x3A, (byte) 0x2F, (byte) 0x2F, (byte) 0x31, (byte) 0x39, (byte) 0x32, (byte) 0x2E,
					(byte) 0x31, (byte) 0x36, (byte) 0x38, (byte) 0x2E, (byte) 0x31, (byte) 0x37, (byte) 0x2E,
					(byte) 0x31, (byte) 0x32, (byte) 0x39, (byte) 0x3A, (byte) 0x38, (byte) 0x30, (byte) 0x37,
					(byte) 0x34, (byte) 0x2F, (byte) 0x73, (byte) 0x65, (byte) 0x72, (byte) 0x69, (byte) 0x61,
					(byte) 0x6C, (byte) 0x69, (byte) 0x7A, (byte) 0x65, (byte) 0x64 });

			Object o2 = new MyClass("http://192.168.2.122:666/constructed");

			System.out.println(o1);
			System.out.println(o2);

			o1 = null;
			o2 = null;

			System.gc();

			System.out.println("Please press enter...");
			System.in.read();
		} catch (Exception ex) {
			ex.printStackTrace(System.err);
		}
	}
}