Finished example.

object-pool/src/main/java/com/iluwatar/Oliphaunt.java

@@ -1,5 +1,21 @@
 package com.iluwatar;
 
 public class Oliphaunt {
-
+	
+	private static int counter = 1;
+	
+	private final int id;
+	
+	public Oliphaunt() {
+		id = counter++;
+	}
+	
+	public int getId() {
+		return id;
+	}
+	
+	@Override
+	public String toString() {
+		return String.format("Oliphaunt id=%d", id);
+	}
 }