Learn java util concurrent part1

Today we are going to learn classes in java package java.util.concurrent. Because there are many classes within java.util.concurrent package, there will be several articles covering classes in this package. Let's start with a simple class first, TimeUnit.

1:  package play.learn.java.concurrent;  
2:    
3:  import java.util.concurrent.BrokenBarrierException;  
4:  import java.util.concurrent.TimeUnit;  
5:    
6:  public class LearnTimeUnit {  
7:       
8:     public LearnTimeUnit() throws InterruptedException {  
9:          
10:        // assuming we have a long running apps which ran for 2 days 7hours 35minutes 6 seconds   
11:        long longRunningApplicationDuration = 200102l;  
12:          
13:        System.out.println("duration in nanos " + TimeUnit.SECONDS.toNanos(longRunningApplicationDuration));  
14:        System.out.println("duration in days " + TimeUnit.SECONDS.toDays(longRunningApplicationDuration));  
15:        System.out.println("duration in hours " + TimeUnit.SECONDS.toHours(longRunningApplicationDuration));  
16:        System.out.println("duration in micros " + TimeUnit.SECONDS.toMicros(longRunningApplicationDuration));  
17:        System.out.println("duration in millis " + TimeUnit.SECONDS.toMillis(longRunningApplicationDuration));  
18:        System.out.println("duration in minutes " + TimeUnit.SECONDS.toMinutes(longRunningApplicationDuration));  
19:        System.out.println("duration in seconds " + TimeUnit.SECONDS.toSeconds(longRunningApplicationDuration));  
20:          
21:          
22:        TimeUnit[] var = TimeUnit.values();  
23:        System.out.println("size " + var.length);  
24:          
25:        for (TimeUnit elem : var) {  
26:           System.out.println(elem.name());  
27:        }  
28:          
29:        TimeUnit.SECONDS.sleep(10);  
30:     }  
31:    
32:     public static void main(String[] args) throws InterruptedException {  
33:        new LearnTimeUnit();  
34:     }  
35:    
36:  }  

TimeUnit provides several helpful methods to convert the time to different unit. You can also download the above source code here.

Next, we will take a look at concurrent exceptions. This exception will become meaningful when we try catch it in the class. For now, we will go through the definition to get a basic understanding of them. Below is a summarization.

BrokenBarrierException
Exception thrown when a thread tries to wait upon a barrier that is in a broken state, or which enters the broken state while the thread is waiting.

CancellationException
Exception indicating that the result of a value-producing task, such as a FutureTask, cannot be retrieved because the task was cancelled.

CompletionException
Exception thrown when an error or other exception is encountered in the course of completing a result or task.

ExecutionException
Exception thrown when attempting to retrieve the result of a task that aborted by throwing an exception. This exception can be inspected using the Throwable.getCause() method.

RejectedExecutionException
Exception thrown by an Executor when a task cannot be accepted for execution.

TimeoutException
Exception thrown when a blocking operation times out. Blocking operations for which a timeout is specified need a means to indicate that the timeout has occurred. For many such operations it is possible to return a value that indicates timeout; when that is not possible or desirable then TimeoutException should be declared and thrown.


BrokenBarrierException example, for full source code, you can download it here.

1:  package play.learn.java.concurrent;  
2:    
3:  import java.util.concurrent.BrokenBarrierException;  
4:  import java.util.concurrent.CyclicBarrier;  
5:    
6:  public class LearnBrokenBarrierException {  
7:       
8:     private CyclicBarrier cibai;  
9:     public static int count = 0;  
10:       
11:     private void manageThread() {  
12:        cibai = new CyclicBarrier(3);  
13:          
14:        for (int i = 0; i < 3; i++) {  
15:           new Thread(new Worker(cibai)).start();  
16:        }  
17:     }  
18:       
19:     public static void barrierComplete(CyclicBarrier cb) {  
20:        System.out.println("collating task");  
21:          
22:        if (count == 3) {  
23:           System.out.println("Exit from system");  
24:           // comment for finite  
25:           System.exit(0);  
26:        }  
27:        count++;  
28:          
29:        for (int i = 0; i < 3; i++) {  
30:        new Thread(new Worker(cb)).start();  
31:        }  
32:     }  
33:       
34:     public static void main(String[] args) {  
35:        new LearnBrokenBarrierException().manageThread();   
36:     }  
37:       
38:     static class Worker implements Runnable {  
39:          
40:        CyclicBarrier cibai;  
41:          
42:        public Worker(CyclicBarrier cb) {  
43:           this.cibai = cb;  
44:        }  
45:          
46:        @Override  
47:        public void run() {  
48:           doSomeWork();  
49:           try {  
50:              if (cibai.await() == 0)  
51:                 LearnBrokenBarrierException.barrierComplete(cibai);  
52:           } catch (InterruptedException e) {  
53:              e.printStackTrace();  
54:           } catch (BrokenBarrierException e) {  
55:              e.printStackTrace();  
56:           }  
57:        }  
58:    
59:        private void doSomeWork() {  
60:           System.out.println("Doing some work");  
61:        }  
62:          
63:     }  
64:    
65:  }  
66:    

CancellationException, ExecutionException, RejectedExecutionException and TimeoutException example, see below. Full source code can be download here.

1:  package play.learn.java.concurrent;  
2:    
3:  import java.util.concurrent.Callable;  
4:  import java.util.concurrent.CancellationException;  
5:  import java.util.concurrent.ExecutionException;  
6:  import java.util.concurrent.ExecutorService;  
7:  import java.util.concurrent.Executors;  
8:  import java.util.concurrent.TimeUnit;  
9:  import java.util.concurrent.TimeoutException;  
10:  import java.util.concurrent.FutureTask;  
11:    
12:  public class LearnCancellationException {  
13:    
14:     public static void main(String[] args) {  
15:        MyCallable callable1 = new MyCallable(1000);  
16:        MyCallable callable2 = new MyCallable(2000);  
17:    
18:        FutureTask<String> futureTask1 = new FutureTask<String>(callable1);  
19:        FutureTask<String> futureTask2 = new FutureTask<String>(callable2);  
20:    
21:        ExecutorService executor = Executors.newFixedThreadPool(2);  
22:        executor.execute(futureTask1);  
23:        executor.execute(futureTask2);  
24:    
25:        while (true) {  
26:           try {  
27:              if(futureTask1.isDone() && futureTask2.isDone()){  
28:                 System.out.println("Done");  
29:                 //shut down executor service  
30:                 executor.shutdown();  
31:                 return;  
32:              }  
33:                
34:              // uncomment for cancel  
35:              //futureTask2.cancel(true);  
36:    
37:              if(!futureTask1.isDone()){  
38:              //wait indefinitely for future task to complete  
39:              System.out.println("FutureTask1 output="+futureTask1.get());  
40:              }  
41:    
42:              System.out.println("Waiting for FutureTask2 to complete");  
43:              // set a samll range to get timedout exception.  
44:              String s = futureTask2.get(2000L, TimeUnit.MILLISECONDS);  
45:              if(s !=null){  
46:                 System.out.println("FutureTask2 output="+s);  
47:              }  
48:           } catch (CancellationException e) {  
49:              e.printStackTrace();  
50:           } catch (InterruptedException | ExecutionException e) {  
51:              e.printStackTrace();  
52:           } catch(TimeoutException e){  
53:              e.printStackTrace();  
54:           }  
55:        }  
56:    
57:     }  
58:       
59:     static class MyCallable implements Callable<String> {  
60:          
61:        private long waitTime;  
62:          
63:        public MyCallable(int timeInMillis) {  
64:           this.waitTime = timeInMillis;  
65:        }  
66:    
67:        @Override  
68:        public String call() throws Exception {  
69:           Thread.sleep(waitTime);  
70:           return Thread.currentThread().getName();  
71:        }  
72:          
73:     }  
74:    
75:  }  
76:    

CompletionException example, for full source code, you can download it here.

1:  public class LearnCompletableFuture {  
2:    
3:     public void learnCompletionException() {  
4:        try {  
5:           List<String> list = Arrays.asList("A", "B", "C", "D");  
6:           list.stream().map(s->CompletableFuture.supplyAsync(() -> s+s))  
7:           .map(f->f.getNow("Not Done")).forEach(s->System.out.println(s));  
8:    
9:        } catch (CompletionException e) {  
10:           e.printStackTrace();  
11:        }  
12:    
13:     }  
14:    
15:     public static void main(String[] args) {  
16:        LearnCompletableFuture c = new LearnCompletableFuture();  
17:        c.learnCompletionException();  
18:     }  
19:  }  

That's it for this article, for the incoming interface and classed until java.util.concurrent which will be publish in the next few articles, until then.

Java Garbage Collector

If you are a java developer, java garbage collection (gc) sometime pop up from time to time in javadoc, online article or online discussion. It is such a hot and tough topic because that is entirely different paradigm than what programmer usually do, that is coding. Java gc free heap for the object you created in class in the background. In the past, I also cover a few article which related to java gc and today I am thinking to go through several blogs/articles which I found online, learn the basic and share what I've learned  and hopefully for java programmer, java gc will become clearer.

When you start a java application, with the parameters that are assigned to the java, the operating system will reserved some memory for java application known as heap. The heap further divided into several regions collectively known as eden, survivor spaces, old gen and perm gens. In oracle java8 hotspot, perm gen has been removed, be sure to always check official documention on garbage collector for changes. Below are a few links for hotspot implementation for java gc.

• java5
• java6 
• java7 
• java8 

Survivor spaces are divided into two, survivor 0 and survivor 1. Both eden and survivor spaces collectively known as Young generation or new generation whilst old gen also known as tenured generation. Garbage collections will happened on young generation and old generations. Below are two diagrams show the heap regions are divided.

While the concept of Garbage Collection is the same, the implementation is not and neither are the default settings or how to tune it. The well known jvm includes the oracle sun hotspot, oracle jrockit and ibm j9. You can find the other jvm lists here. Essentially garbage collection will perform on young generation and old generation to remove object on heap that has no valid reference.

common java parameters settings. For full list, issue the command java -X

-Xms initial java heap size

-Xmx maximum java heap size

-Xmn the size of the heap for the young generation

There are a few type of GC

- serial gc

- parallel gc

- parallel old gc

- cms gc 

- g1 gc

You can specify what gc implementation to run on the java heap region.

If you run a server application, the metric exposed by gc is definitely to watch out for. In order to get the metric, you can use

* jstat

* gc logging

That's it for this brief introduction.

Yet another hdd vs ssd comparison

There are many article online that articulate how fast a solid state drive in comparison to a spinning hard disk drive. But ones wonder really, just how fast is ssd. I mean if your earning is limited and the current spinning disk is working fine, there is no compelling reason to make the change and at the same time, it will be difficult to afford a ssd considering the cost per gb. As of this writing, a samsung 850 pro 512GB selling at compuzone malaysia at a staggering pricing of 1378MYR!!! But there is a kind soul who generously donate ssd to me and as a gesture of good will back to him, here in I will write a blog describe my experience migrating from a Hitachi/HGST Travelstar Z7K500 HGST HTS725050A7E630 to a Samsung SSD 850 PRO 512GB.

One things for sure, ssd weight is so light. It is only 66gram! In comparison with hdd at 95gram. For the first timer, ssd weight is so light that it confused me like did it actually contain the size of 512GB.

For the spinning hdd, I took 5 samples, 1min 41sec, 1min 34sec, 1min 34sec, 1min 34sec and 1min 31sec. All measurements from the moment I push the power button until I see the login screen. Of cause, there many services running during bootup. On average, the bootup time is around  1min 48sec.

Next, I benchmark the current hdd with hdparm and dd.

 user@localhost:~$ sudo hdparm -t /dev/sda5  
   
 /dev/sda5:  
  Timing buffered disk reads: 322 MB in 3.01 seconds = 107.12 MB/sec  
 user@localhost:~$ sudo hdparm -t /dev/sda5  
   
 /dev/sda5:  
  Timing buffered disk reads: 322 MB in 3.01 seconds = 107.13 MB/sec  
 user@localhost:~$ sudo hdparm -t /dev/sda5  
   
 /dev/sda5:  
  Timing buffered disk reads: 322 MB in 3.01 seconds = 107.12 MB/sec  
   
   
 user@localhost:~$ sudo hdparm -T /dev/sda5  
   
 /dev/sda5:  
  Timing cached reads:  5778 MB in 2.00 seconds = 2889.25 MB/sec  
 user@localhost:~$ sudo hdparm -T /dev/sda5  
   
 /dev/sda5:  
  Timing cached reads:  5726 MB in 2.00 seconds = 2863.32 MB/sec  
 user@localhost:~$ sudo hdparm -T /dev/sda5  
   
 /dev/sda5:  
  Timing cached reads:  5702 MB in 2.00 seconds = 2850.84 MB/sec  

I have performed 3 tests with cache and without cache reading. On average, non caching read speed is about 107.12MB/sec and caching read speed is 2867.80MB/sec . The parameter for hdparm is shown below.

       -t     Perform timings of device reads for benchmark and comparison purposes.  For meaningful results, this operation should be repeated 2-3 times on an otherwise inactive system
(no  other active processes) with at least a couple of megabytes of free memory.  This displays the speed of reading through the buffer cache to the disk without any prior caching of data.  This measurement is an indication of how fast the drive can sustain sequential data reads under Linux, without any filesystem overhead.  To ensure  accurate measurements, the buffer cache is flushed during the processing of -t using the BLKFLSBUF ioctl.

       -T     Perform  timings of cache reads for benchmark and comparison purposes.  For meaningful results, this operation should be repeated 2-3 times on an otherwise inactive system
 (no other active processes) with at least a couple of megabytes of free memory.  This displays the speed of reading directly from  the  Linux  buffer  cache  without  disk access.  This measurement is essentially an indication of the throughput of the processor, cache, and memory of the system under test.

Next, I use command dd to do higher layer benchmark on the disk. See below.

 user@localhost:~$ time sh -c "dd if=/dev/zero of=ddfile bs=8k count=250000 && sync"; rm -f ddfile  
 250000+0 records in  
 250000+0 records out  
 2048000000 bytes (2.0 GB) copied, 32.5028 s, 63.0 MB/s  
   
 real     0m41.773s  
 user     0m0.068s  
 sys     0m4.048s  
 user@localhost:~$ time sh -c "dd if=/dev/zero of=ddfile bs=8k count=250000 && sync"; rm -f ddfile  
 250000+0 records in  
 250000+0 records out  
 2048000000 bytes (2.0 GB) copied, 27.1676 s, 75.4 MB/s  
   
 real     0m37.012s  
 user     0m0.056s  
 sys     0m3.848s  
 user@localhost:~$ time sh -c "dd if=/dev/zero of=ddfile bs=8k count=250000 && sync"; rm -f ddfile  
 250000+0 records in  
 250000+0 records out  
 2048000000 bytes (2.0 GB) copied, 19.4599 s, 105 MB/s  
   
 real     0m37.929s  
 user     0m0.064s  
 sys     0m3.740s  

So the arithmetic, ( 8 x 1024 x 250000 / 2014 / 1024 ) / real so that give 46.75MB/sec, 52.77MB/sec and 51.49MB/sec respectively on all three tests and on average 50.33MB/sec.

Now to the samsung ssd.

 root@localhost:~# sudo hdparm -t /dev/sda6  
   
 /dev/sda6:  
  Timing buffered disk reads: 770 MB in 3.01 seconds = 256.00 MB/sec  
 root@localhost:~# sudo hdparm -t /dev/sda6  
   
 /dev/sda6:  
  Timing buffered disk reads: 762 MB in 3.00 seconds = 253.98 MB/sec  
 root@localhost:~# sudo hdparm -t /dev/sda6  
   
 /dev/sda6:  
  Timing buffered disk reads: 758 MB in 3.00 seconds = 252.44 MB/sec  
   
   
 root@localhost:~# sudo hdparm -T /dev/sda6   
   
 /dev/sda6:  
  Timing cached reads:  5820 MB in 2.00 seconds = 2910.31 MB/sec  
 root@localhost:~# sudo hdparm -T /dev/sda6   
   
 /dev/sda6:  
  Timing cached reads:  6022 MB in 2.00 seconds = 3011.33 MB/sec  
 root@localhost:~# sudo hdparm -T /dev/sda6   
   
 /dev/sda6:  
  Timing cached reads:  5698 MB in 2.00 seconds = 2849.14 MB/sec  
 root@localhost:~#   
   
   
 root@localhost:~# time sh -c "dd if=/dev/zero of=ddfile bs=8k count=250000 && sync"; rm -f ddfile   
 250000+0 records in  
 250000+0 records out  
 2048000000 bytes (2.0 GB) copied, 4.14268 s, 494 MB/s  
   
 real     0m8.280s  
 user     0m0.040s  
 sys     0m2.084s  
 root@localhost:~# time sh -c "dd if=/dev/zero of=ddfile bs=8k count=250000 && sync"; rm -f ddfile   
 250000+0 records in  
 250000+0 records out  
 2048000000 bytes (2.0 GB) copied, 4.18595 s, 489 MB/s  
   
 real     0m8.279s  
 user     0m0.068s  
 sys     0m2.036s  
 root@localhost:~# time sh -c "dd if=/dev/zero of=ddfile bs=8k count=250000 && sync"; rm -f ddfile   
 250000+0 records in  
 250000+0 records out  
 2048000000 bytes (2.0 GB) copied, 3.94227 s, 519 MB/s  
   
 real     0m8.258s  
 user     0m0.080s  
 sys     0m2.060s  
   

On average, non caching read speed is 253.67MB/sec and caching read speed is 2926.93MB/sec. As for dd tests, on average, 236.10MB/sec. On average, the bootup time is around  30sec! The significant change is during after grub and the login shown is around 3 seconds or less. Although the rated for this ssd for sequantil read and write is 550/520MB/sec, maybe it was because of my old system bandwidth maxing out.

Significant time reduced during bootup and disk read is clearly seen from the statistics above. As for user experience, everything become so fast! To put into comparison, hdd to ssd is like proton car to F1 car. I think in the future, it will help in term of programming like code grepping and code find.

UPDATE: with adjustment to the grub timeout and changes to the POST to fast boot, now my cold boot to login screen is improved to 20seconds!

Light learning into CouchDB

Today we will explore another opensource database, CouchDB. First, let's understand what is Apache CouchDB

Apache CouchDB, commonly referred to as CouchDB, is an open source database that focuses on ease of use and on being "a database that completely embraces the web".[1] It is a document-oriented NoSQL database that uses JSON to store data, JavaScript as its query language using MapReduce, and HTTP for an API.[1] CouchDB was first released in 2005 and later became an Apache project in 2008.

Actually couch is an acronym for Cluster Of Unreliable Commodity Hardware.  If you are using debian based linux distribution, it will be very easy, just apt-get install couchdb . If not, you can check out this link on how to install for other linux distribution. Once installed, make sure couchdb is running.

 root@localhost:~# /etc/init.d/couchdb status  
 ● couchdb.service - LSB: Apache CouchDB init script  
   Loaded: loaded (/etc/init.d/couchdb)  
   Active: active (exited) since Thu 2015-08-20 23:07:30 MYT; 14s ago  
    Docs: man:systemd-sysv-generator(8)  
   
 Aug 20 23:07:28 localhost systemd[1]: Starting LSB: Apache CouchDB init script...  
 Aug 20 23:07:28 localhost su[14399]: Successful su for couchdb by root  
 Aug 20 23:07:28 localhost su[14399]: + ??? root:couchdb  
 Aug 20 23:07:28 localhost su[14399]: pam_unix(su:session): session opened for user couchdb by (uid=0)  
 Aug 20 23:07:30 localhost couchdb[14392]: Starting database server: couchdb.  
 Aug 20 23:07:30 localhost systemd[1]: Started LSB: Apache CouchDB init script.  
   

very easy, you can quickly check the version of couchdb that is running. just put the following link into the browser.

http://127.0.0.1:5984/

I have version 1.4.0 running. Let's create a database. If you have terminal ready, you can copy and paste below and check the database created.

 user@localhost:~$ curl -X PUT http://127.0.0.1:5984/wiki  
 {"ok":true}  
 user@localhost:~$ curl -X PUT http://127.0.0.1:5984/wiki  
 {"error":"file_exists","reason":"The database could not be created, the file already exists."}  
 user@localhost:~$ curl http://127.0.0.1:5984/wiki  
 {"db_name":"wiki","doc_count":0,"doc_del_count":0,"update_seq":0,"purge_seq":0,"compact_running":false,"disk_size":79,"data_size":0,"instance_start_time":"1440083544219325","disk_format_version":6,"committed_update_seq":0}  
 user@localhost:~$ curl -X GET http://127.0.0.1:5984/_all_dbs  
 ["_replicator","_users","wiki"]  

couchdb has json output, key value output and error handling is pretty good. Very speedy too! okay now, let's try on crud on couchdb and we will do that using curl.

 user@localhost:~$ curl -X POST -H "Content-Type: application/json" --data '{ "text" : "Wikipedia on CouchDB", "rating": 5 }' http://127.0.0.1:5984/wiki  
 {"ok":true,"id":"4c6a6dce960e16aba7e50d02c9001241","rev":"1-80fd6f7aeb55c83c8999b4613843af5d"}  
   
 user@localhost:~$ curl -X GET -H "Content-Type: application/json" http://127.0.0.1:5984/wiki/4c6a6dce960e16aba7e50d02c9001241  
 {"_id":"4c6a6dce960e16aba7e50d02c9001241","_rev":"1-80fd6f7aeb55c83c8999b4613843af5d","text":"Wikipedia on CouchDB","rating":5}  

first, we create a new document by http post with data in json format. Then using the id that couchdb generated, we get that document data back.

 user@localhost:~$ curl -X PUT -H "Content-Type: application/json" --data '{ "text" : "Wikipedia on CouchDB", "rating": 6, "_rev": "1-80fd6f7aeb55c83c8999b4613843af5d" }' http://127.0.0.1:5984/wiki/4c6a6dce960e16aba7e50d02c9001241  
 {"ok":true,"id":"4c6a6dce960e16aba7e50d02c9001241","rev":"2-b7248b6af9b6efcea5a8fe8cc299a85c"}  
 user@localhost:~$ curl -X GET -H "Content-Type: application/json" http://127.0.0.1:5984/wiki/4c6a6dce960e16aba7e50d02c9001241  
 {"_id":"4c6a6dce960e16aba7e50d02c9001241","_rev":"2-b7248b6af9b6efcea5a8fe8cc299a85c","text":"Wikipedia on CouchDB","rating":6}  
 user@localhost:~$ curl -X PUT -H "Content-Type: application/json" --data '{ "views" : 10, "_rev": "2-b7248b6af9b6efcea5a8fe8cc299a85c" }' http://127.0.0.1:5984/wiki/4c6a6dce960e16aba7e50d02c9001241  
 {"ok":true,"id":"4c6a6dce960e16aba7e50d02c9001241","rev":"3-9d1c59138f909760f9de6e5ce63c3a4e"}  
 user@localhost:~$ curl -X GET -H "Content-Type: application/json" http://127.0.0.1:5984/wiki/4c6a6dce960e16aba7e50d02c9001241  
 {"_id":"4c6a6dce960e16aba7e50d02c9001241","_rev":"3-9d1c59138f909760f9de6e5ce63c3a4e","views":10}  

As you can read above, we update this document twice, first, we update by increase rating to 6 and appending _rev using a unique id generated from couchdb. If this update is a success, notice that rev is increase by 1? note 2- on rev. On the second update, we update the view to 10 but essentially in couchdb, everything in this doc is wipe and insert a new key called views. So note if you want to update a document, you should send in all existing value before do the update.

Finally, now we delete this document. Very easy, see below.

 user@localhost:~$ curl -X DELETE -H "Content-Type: application/json" http://127.0.0.1:5984/wiki/4c6a6dce960e16aba7e50d02c9001241?rev=3-9d1c59138f909760f9de6e5ce63c3a4e  
 {"ok":true,"id":"4c6a6dce960e16aba7e50d02c9001241","rev":"4-aa379357deff42739d2fc77aea38dde1"}  
 user@localhost:~$ curl -X GET -H "Content-Type: application/json" http://127.0.0.1:5984/wiki/4c6a6dce960e16aba7e50d02c9001241  
 {"error":"not_found","reason":"deleted"}  
 user@localhost:~$ curl -X DELETE http://127.0.0.1:5984/wiki  
 {"ok":true}  
 user@localhost:~$ curl -X GET http://127.0.0.1:5984/_all_dbs  
 ["_replicator","_users"]  

couchdb is very good and efficient of handling document, it certainly definitely earn it spot for beginner to dwelve deeper of its capability. If you think so, take a look at this link. That's it for today, have fun learning!

Apache accumulo first learning experience

Today we will take a look into another big data technology. Apache accumulo is the topic for today. First, what is accumulo?

Apache Accumulo is based on Google's BigTable design and is built on top of Apache Hadoop, Zookeeper, and Thrift. Apache Accumulo features a few novel improvements on the BigTable design in the form of cell-based access control and a server-side programming mechanism that can modify key/value pairs at various points in the data management process. Other notable improvements and feature are outlined here.

Google published the design of BigTable in 2006. Several other open source projects have implemented aspects of this design including HBase, Hypertable, and Cassandra. Accumulo began its development in 2008 and joined the Apache community in 2011.

In this article, as always, we will setup the infrastructure. I reference this article with the following environment.

• 64bit arch
• open jdk 1.7/1.8
• zookeeper-3.4.6
• hadoop-2.6.1
• accumulo-1.7.0
• openssh 
• rsync
• debian sid

As accumulo is java based project, you must installed and configured java. Get latest java 1.7 or 1.8 as of this writing. After java is installed you need to export JAVA_HOME in your bash configuration file, .bashrc with this line export JAVA_HOME=/usr/lib/jvm/jdk1.7.0_55

Then you need to source the new .bashrc. . .bashrc is sufficient. For ssh and rsync, you can use apt-get package manager as it is easy. What's important is that, you should enable public and private key in your user configuration ssh directory. 

You can create two directories, $HOME/Downloads and $HOME/Installs respectively. It's pretty intuitive, the downloads directory is for the package downloaded and the install is the working directory after the compress packages are downloaded.

http://www.eu.apache.org/dist/zookeeper/zookeeper-3.4.6/

http://www.apache.org/dyn/closer.cgi/hadoop/common/hadoop-2.6.1/hadoop-2.6.1.tar.gz

https://www.apache.org/dyn/closer.lua/accumulo/1.7.0/accumulo-1.7.0-bin.tar.gz

Download the above packages into the $HOME/Downloads directory and extracted into $HOME/Installs. First, let's configure apache hadoop.

 $ vim $HOME/Installs/hadoop-2.6.1/etc/hadoop/hadoop-env.sh  
 $ # uncomment in the file above export JAVA_HOME=/usr/lib/jvm/jdk1.7.0_55  
 $ vim $HOME/Installs/hadoop-2.6.1/etc/hadoop/core-site.xml  
 $ cat $HOME/Installs/hadoop-2.6.1/etc/hadoop/core-site.xml  
 <?xml version="1.0" encoding="UTF-8"?>  
 <?xml-stylesheet type="text/xsl" href="configuration.xsl"?>  
 <configuration>  
   <property>  
     <name>fs.defaultFS</name>  
     <value>hdfs://localhost:9000</value>  
   </property>  
 </configuration>  
 $ vim $HOME/Installs/hadoop-2.6.1/etc/hadoop/hdfs-site.xml  
 $ cat $HOME/Installs/hadoop-2.6.1/etc/hadoop/hdfs-site.xml  
 <?xml version="1.0" encoding="UTF-8"?>  
 <?xml-stylesheet type="text/xsl" href="configuration.xsl"?>  
 <configuration>  
   <property>  
     <name>dfs.replication</name>  
     <value>1</value>  
   </property>  
   <property>  
     <name>dfs.name.dir</name>  
     <value>hdfs_storage/name</value>  
   </property>  
   <property>  
     <name>dfs.data.dir</name>  
     <value>hdfs_storage/data</value>  
   </property>  
 </configuration>  
 $ vim $HOME/Installs/hadoop-2.6.1/etc/hadoop/mapred-site.xml  
 $ cat $HOME/Installs/hadoop-2.6.1/etc/hadoop/mapred-site.xml  
 <?xml version="1.0"?>  
 <?xml-stylesheet type="text/xsl" href="configuration.xsl"?>  
 <configuration>  
    <property>  
      <name>mapred.job.tracker</name>  
      <value>localhost:9001</value>  
    </property>  
 </configuration>  
 $ cd $HOME/Installs/hadoop-2.6.1/  
 $ $HOME/Installs/hadoop-2.6.1/bin/hdfs namenode -format  
 $ $HOME/Installs/hadoop-2.6.1/sbin/start-dfs.sh  

As you can read above, we specify the java home for hadoop and then we configure hadoop to run on port 9000, so make sure this port is free for hadoop to use. Then we format the hadoop namenode and start the hadoop.

Next we will configure zookeeper.

 $ cp $HOME/Installs/zookeeper-3.4.6/conf/zoo_sample.cfg $HOME/Installs/zookeeper-3.4.6/conf/zoo.cfg  
 $ $HOME/Installs/zookeeper-3.4.6/bin/zkServer.sh start  

Pretty simple, get the default config file and start the services. Last steps is the apache accumulo.

 $ cp $HOME/Installs/accumulo-1.7.0/conf/examples/512MB/standalone/* $HOME/Installs/accumulo-1.7.0/conf/  
 $ vim $HOME/.bashrc  
 $ tail -2 $HOME/.bashrc  
 export HADOOP_HOME=$HOME/Installs/hadoop-2.6.1/  
 export ZOOKEEPER_HOME=$HOME/Installs/zookeeper-3.4.6/  
 $ . $HOME/.bashrc  
 $ vim $HOME/Installs/accumulo-1.7.0/conf/accumulo-env.sh  
 $ # SET ACCUMULO_MONITOR_BIND_ALL to true.  
 $ vim $HOME/Installs/accumulo-1.7.0/conf/accumulo-site.xml  
 $ # in file $HOME/Installs/accumulo-1.7.0/conf/accumulo-site.xml  
 <property>  
   <name>instance.volumes</name>  
   <value>hdfs://localhost:9000/accumulo</value>  
 </property>  
 $ # in file $HOME/Installs/accumulo-1.7.0/conf/accumulo-site.xml   
   <name>instance.secret</name>  
   <value>mysecret</value>  
 $ # in file $HOME/Installs/accumulo-1.7.0/conf/accumulo-site.xml    
  <property>  
   <name>trace.token.property.password</name>  
   <value>my scret</value>  
  </property>  

So we have configure the setting for accumulo in .bashrc and some properties settings in accumulo-env.sh and accumulo-site.xml . Next, we will initialize accumulo and start it using the password we specify previously.

 $ $HOME/Installs/accumulo-1.7.0/bin/accumulo init  
 $ # give a instance name.  
 $ # type in the password as specify in trace.token.property.password.  
 $ $HOME/Installs/accumulo-1.7.0/bin/start-all.sh  

That's it! If you want to do CRUD in accumulo, I suggest you go with this official documentation.

Learning basic of apache karaf

Recently container is such a hot topic especially from docker and today, we will look into another container from apache. Today, we will take a look into Apache Karaf.

What is Apache Karaf?

Apache Karaf is a small OSGi based runtime which provides a lightweight container onto which various components and applications can be deployed.

If you have no idea what does that means, maybe a simple quick how to give some idea. First, let's download a copy of apache karaf and you can do that just here. At the time of this learning experience, I'm using Apache Karaf version 4.0.1. Then extract to a path so that will be karaf home directory.

 user@localhost:~/Desktop$ ll apache-karaf-4.0.1.tar.gz   
 -rw-r----- 1 user user 16M Oct 5 22:35 apache-karaf-4.0.1.tar.gz  
 user@localhost:~/Desktop$ tar -zxf apache-karaf-4.0.1.tar.gz   
 user@localhost:~/Desktop$ cd apache-karaf-4.0.1  
 apache-karaf-4.0.1/    apache-karaf-4.0.1.tar.gz   
 user@localhost:~/Desktop$ cd apache-karaf-4.0.1  
 user@localhost:~/Desktop/apache-karaf-4.0.1$ ls  
 bin data demos deploy etc lib LICENSE NOTICE README RELEASE-NOTES system  

So apache is about 16MB compressed and contain a few directories to work with.

The directory layout of a Karaf installation is as follows:
/bin: control scripts to start, stop, login.
/demos: contains some simple Karaf samples
/etc: configuration files
/data: working directory
/cache: OSGi framework bundle cache
/generated-bundles: temporary folder used by the deployers
/log: log files
/deploy: hot deploy directory
/instances: directory containing instances
/lib: contains libraries
/lib/boot: contains the system libraries used at Karaf bootstrap
/lib/endorsed: directory for endorsed libraries
/lib/ext: directory for JRE extensions
/system: OSGi bundles repository, laid out as a Maven 2 repository

Let's launch karaf, see screenshot below in the terminal. Let's add apache camel repository into apache karaf and then install on it. We will therefore using this as a sample for this learning experience.

 karaf@root()> feature:repo-add camel 2.15.3  
 Adding feature url mvn:org.apache.camel.karaf/apache-camel/2.15.3/xml/features  
 karaf@root()> feature:info camel  
 Feature camel 2.15.3  
 Feature has no configuration  
 Feature has no configuration files  
 Feature depends on:  
  camel-core 2.15.3  
  camel-spring 2.15.3  
  camel-blueprint 2.15.3  
 Feature has no bundles.  
 Feature has no conditionals.  
 karaf@root()> feature:install camel-spring  
 karaf@root()> bundle:install -s mvn:org.apache.camel/camel-example-osgi/2.15.3  
 Bundle ID: 82  
 karaf@root()> log:display  
 2015-10-05 22:41:37,872 | INFO | pool-17-thread-1 | core               | 17 - org.apache.aries.jmx.core - 1.1.3 | Registering org.osgi.jmx.framework.BundleStateMBean to MBeanServer com.sun.jmx.mbeanserver.JmxMBeanServer@dd1e765 with name osgi.core:type=bundleState,version=1.7,framework=org.apache.felix.framework,uuid=e7d79bed-237a-4c4d-b912-920b57fef63b  
 2015-10-05 22:41:37,876 | INFO | pool-17-thread-1 | core               | 17 - org.apache.aries.jmx.core - 1.1.3 | Registering org.osgi.jmx.service.cm.ConfigurationAdminMBean to MBeanServer com.sun.jmx.mbeanserver.JmxMBeanServer@dd1e765 with name osgi.compendium:service=cm,version=1.3,framework=org.apache.felix.framework,uuid=e7d79bed-237a-4c4d-b912-920b57fef63b  
 2015-10-05 22:41:37,876 | INFO | pool-17-thread-1 | core               | 17 - org.apache.aries.jmx.core - 1.1.3 | Registering org.osgi.jmx.framework.wiring.BundleWiringStateMBean to MBeanServer com.sun.jmx.mbeanserver.JmxMBeanServer@dd1e765 with name osgi.core:type=wiringState,version=1.1,framework=org.apache.felix.framework,uuid=e7d79bed-237a-4c4d-b912-920b57fef63b  
 2015-10-05 22:41:37,877 | INFO | pool-17-thread-1 | core               | 17 - org.apache.aries.jmx.core - 1.1.3 | Registering org.osgi.jmx.framework.FrameworkMBean to MBeanServer com.sun.jmx.mbeanserver.JmxMBeanServer@dd1e765 with name osgi.core:type=framework,version=1.7,framework=org.apache.felix.framework,uuid=e7d79bed-237a-4c4d-b912-920b57fef63b  
 2015-10-05 22:41:37,878 | INFO | pool-17-thread-1 | core               | 17 - org.apache.aries.jmx.core - 1.1.3 | Registering org.osgi.jmx.framework.PackageStateMBean to MBeanServer com.sun.jmx.mbeanserver.JmxMBeanServer@dd1e765 with name osgi.core:type=packageState,version=1.5,framework=org.apache.felix.framework,uuid=e7d79bed-237a-4c4d-b912-920b57fef63b  
 2015-10-05 22:41:37,878 | INFO | pool-17-thread-1 | core               | 17 - org.apache.aries.jmx.core - 1.1.3 | Registering org.osgi.jmx.framework.ServiceStateMBean to MBeanServer com.sun.jmx.mbeanserver.JmxMBeanServer@dd1e765 with name osgi.core:type=serviceState,version=1.7,framework=org.apache.felix.framework,uuid=e7d79bed-237a-4c4d-b912-920b57fef63b  
 2015-10-05 22:41:38,145 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Registering commands for bundle org.apache.karaf.bundle.core/4.0.1  
 2015-10-05 22:41:38,168 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Registering commands for bundle org.apache.karaf.config.core/4.0.1  
 2015-10-05 22:41:38,178 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Registering commands for bundle org.apache.karaf.deployer.kar/4.0.1  
 2015-10-05 22:41:38,180 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Registering commands for bundle org.apache.karaf.diagnostic.core/4.0.1  
 2015-10-05 22:41:38,204 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Registering commands for bundle org.apache.karaf.features.command/4.0.1  
 2015-10-05 22:41:38,230 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Registering commands for bundle org.apache.karaf.instance.core/4.0.1  
 2015-10-05 22:41:38,256 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Registering commands for bundle org.apache.karaf.jaas.command/4.0.1  
 2015-10-05 22:41:38,259 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Updating commands for bundle org.apache.karaf.jaas.command/4.0.1  
 2015-10-05 22:41:38,260 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Updating commands for bundle org.apache.karaf.jaas.command/4.0.1  
 2015-10-05 22:41:38,266 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Registering commands for bundle org.apache.karaf.kar.core/4.0.1  
 2015-10-05 22:41:38,277 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Registering commands for bundle org.apache.karaf.log.core/4.0.1  
 2015-10-05 22:41:38,281 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Registering commands for bundle org.apache.karaf.package.core/4.0.1  
 2015-10-05 22:41:38,285 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Registering commands for bundle org.apache.karaf.service.core/4.0.1  
 2015-10-05 22:41:38,327 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Command registration delayed for bundle org.apache.karaf.shell.commands/4.0.1. Missing dependencies: [org.jledit.EditorFactory]  
 2015-10-05 22:41:38,581 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Command registration delayed for bundle org.apache.karaf.shell.ssh/4.0.1. Missing dependencies: [org.apache.sshd.SshServer]  
 2015-10-05 22:41:38,593 | INFO | pool-23-thread-1 | SecurityUtils          | 47 - org.apache.sshd.core - 0.14.0 | BouncyCastle not registered, using the default JCE provider  
 2015-10-05 22:41:38,624 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Registering commands for bundle org.apache.karaf.system.core/4.0.1  
 2015-10-05 22:41:38,631 | INFO | FelixStartLevel | CommandExtension         | 43 - org.apache.karaf.shell.core - 4.0.1 | Registering commands for bundle org.apache.karaf.shell.commands/4.0.1  
 2015-10-05 23:18:09,193 | INFO | nsole user karaf | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 | Adding features: camel-spring/[2.15.3,2.15.3]  
 2015-10-05 23:19:30,370 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 | Changes to perform:  
 2015-10-05 23:19:30,371 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  Region: root  
 2015-10-05 23:19:30,371 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |   Bundles to install:  
 2015-10-05 23:19:30,371 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.camel/camel-catalog/2.15.3  
 2015-10-05 23:19:30,371 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.camel/camel-commands-core/2.15.3  
 2015-10-05 23:19:30,372 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.camel/camel-core/2.15.3  
 2015-10-05 23:19:30,372 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.camel/camel-spring/2.15.3  
 2015-10-05 23:19:30,372 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.camel.karaf/camel-karaf-commands/2.15.3  
 2015-10-05 23:19:30,373 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.geronimo.specs/geronimo-jta_1.1_spec/1.1.1  
 2015-10-05 23:19:30,373 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.karaf.bundle/org.apache.karaf.bundle.springstate/4.0.1  
 2015-10-05 23:19:30,373 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.karaf.deployer/org.apache.karaf.deployer.spring/4.0.1  
 2015-10-05 23:19:30,373 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.aopalliance/1.0_6  
 2015-10-05 23:19:30,374 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.cglib/3.0_1  
 2015-10-05 23:19:30,374 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.jaxb-impl/2.2.6_1  
 2015-10-05 23:19:30,374 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.spring-aop/3.2.14.RELEASE_1  
 2015-10-05 23:19:30,374 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.spring-beans/3.2.14.RELEASE_1  
 2015-10-05 23:19:30,375 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.spring-context/3.2.14.RELEASE_1  
 2015-10-05 23:19:30,375 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.spring-context-support/3.2.14.RELEASE_1  
 2015-10-05 23:19:30,375 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.spring-core/3.2.14.RELEASE_1  
 2015-10-05 23:19:30,375 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.spring-expression/3.2.14.RELEASE_1  
 2015-10-05 23:19:30,376 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.spring-tx/3.2.14.RELEASE_1  
 2015-10-05 23:19:30,376 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.springframework/spring-aop/3.1.4.RELEASE  
 2015-10-05 23:19:30,376 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.springframework/spring-asm/3.1.4.RELEASE  
 2015-10-05 23:19:30,377 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.springframework/spring-beans/3.1.4.RELEASE  
 2015-10-05 23:19:30,377 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.springframework/spring-context/3.1.4.RELEASE  
 2015-10-05 23:19:30,377 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.springframework/spring-context-support/3.1.4.RELEASE  
 2015-10-05 23:19:30,377 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.springframework/spring-core/3.1.4.RELEASE  
 2015-10-05 23:19:30,378 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.springframework/spring-expression/3.1.4.RELEASE  
 2015-10-05 23:19:30,378 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.springframework.osgi/spring-osgi-core/1.2.1  
 2015-10-05 23:19:30,378 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.springframework.osgi/spring-osgi-extender/1.2.1  
 2015-10-05 23:19:30,378 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.springframework.osgi/spring-osgi-annotation/1.2.1  
 2015-10-05 23:19:30,379 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.springframework.osgi/spring-osgi-io/1.2.1  
 2015-10-05 23:19:30,379 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.codehaus.woodstox/stax2-api/3.1.4  
 2015-10-05 23:19:30,380 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |    mvn:org.codehaus.woodstox/woodstox-core-asl/4.4.1  
 2015-10-05 23:19:30,383 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 | Installing bundles:  
 2015-10-05 23:19:30,383 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.camel/camel-catalog/2.15.3  
 2015-10-05 23:19:30,393 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.camel/camel-commands-core/2.15.3  
 2015-10-05 23:19:30,399 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.camel/camel-core/2.15.3  
 2015-10-05 23:19:30,436 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.camel/camel-spring/2.15.3  
 2015-10-05 23:19:30,447 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.camel.karaf/camel-karaf-commands/2.15.3  
 2015-10-05 23:19:30,451 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.geronimo.specs/geronimo-jta_1.1_spec/1.1.1  
 2015-10-05 23:19:30,453 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.karaf.bundle/org.apache.karaf.bundle.springstate/4.0.1  
 2015-10-05 23:19:30,458 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.karaf.deployer/org.apache.karaf.deployer.spring/4.0.1  
 2015-10-05 23:19:30,462 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.aopalliance/1.0_6  
 2015-10-05 23:19:30,465 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.cglib/3.0_1  
 2015-10-05 23:19:30,471 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.jaxb-impl/2.2.6_1  
 2015-10-05 23:19:30,485 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.spring-aop/3.2.14.RELEASE_1  
 2015-10-05 23:19:30,498 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.spring-beans/3.2.14.RELEASE_1  
 2015-10-05 23:19:30,510 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.spring-context/3.2.14.RELEASE_1  
 2015-10-05 23:19:30,536 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.spring-context-support/3.2.14.RELEASE_1  
 2015-10-05 23:19:30,545 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.spring-core/3.2.14.RELEASE_1  
 2015-10-05 23:19:30,560 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.spring-expression/3.2.14.RELEASE_1  
 2015-10-05 23:19:30,567 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.apache.servicemix.bundles/org.apache.servicemix.bundles.spring-tx/3.2.14.RELEASE_1  
 2015-10-05 23:19:30,576 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.springframework/spring-aop/3.1.4.RELEASE  
 2015-10-05 23:19:30,585 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.springframework/spring-asm/3.1.4.RELEASE  
 2015-10-05 23:19:30,590 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.springframework/spring-beans/3.1.4.RELEASE  
 2015-10-05 23:19:30,606 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.springframework/spring-context/3.1.4.RELEASE  
 2015-10-05 23:19:30,636 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.springframework/spring-context-support/3.1.4.RELEASE  
 2015-10-05 23:19:30,655 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.springframework/spring-core/3.1.4.RELEASE  
 2015-10-05 23:19:30,667 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.springframework/spring-expression/3.1.4.RELEASE  
 2015-10-05 23:19:30,673 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.springframework.osgi/spring-osgi-core/1.2.1  
 2015-10-05 23:19:30,684 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.springframework.osgi/spring-osgi-extender/1.2.1  
 2015-10-05 23:19:30,691 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.springframework.osgi/spring-osgi-annotation/1.2.1  
 2015-10-05 23:19:30,696 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.springframework.osgi/spring-osgi-io/1.2.1  
 2015-10-05 23:19:30,702 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.codehaus.woodstox/stax2-api/3.1.4  
 2015-10-05 23:19:30,708 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  mvn:org.codehaus.woodstox/woodstox-core-asl/4.4.1  
 2015-10-05 23:19:31,219 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 | Starting bundles:  
 2015-10-05 23:19:31,337 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.servicemix.bundles.aopalliance/1.0.0.6  
 2015-10-05 23:19:31,339 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.springframework.asm/3.1.4.RELEASE  
 2015-10-05 23:19:31,341 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.springframework.core/3.1.4.RELEASE  
 2015-10-05 23:19:31,343 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.springframework.beans/3.1.4.RELEASE  
 2015-10-05 23:19:31,344 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.springframework.aop/3.1.4.RELEASE  
 2015-10-05 23:19:31,346 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.springframework.expression/3.1.4.RELEASE  
 2015-10-05 23:19:31,347 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.springframework.context/3.1.4.RELEASE  
 2015-10-05 23:19:31,349 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.servicemix.bundles.cglib/3.0.0.1  
 2015-10-05 23:19:31,352 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.servicemix.bundles.spring-core/3.2.14.RELEASE_1  
 2015-10-05 23:19:31,354 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.servicemix.bundles.spring-beans/3.2.14.RELEASE_1  
 2015-10-05 23:19:31,356 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.servicemix.bundles.spring-aop/3.2.14.RELEASE_1  
 2015-10-05 23:19:31,357 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.springframework.osgi.io/1.2.1  
 2015-10-05 23:19:31,359 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.servicemix.bundles.spring-expression/3.2.14.RELEASE_1  
 2015-10-05 23:19:31,360 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.servicemix.bundles.spring-context/3.2.14.RELEASE_1  
 2015-10-05 23:19:31,362 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.springframework.osgi.core/1.2.1  
 2015-10-05 23:19:31,364 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.springframework.osgi.extensions.annotations/1.2.1  
 2015-10-05 23:19:31,366 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.springframework.osgi.extender/1.2.1  
 2015-10-05 23:19:31,393 | INFO | pool-25-thread-1 | ContextLoaderListener      | 77 - org.springframework.osgi.extender - 1.2.1 | Starting [org.springframework.osgi.extender] bundle v.[1.2.1]  
 2015-10-05 23:19:31,727 | INFO | pool-25-thread-1 | ExtenderConfiguration      | 77 - org.springframework.osgi.extender - 1.2.1 | No custom extender configuration detected; using defaults...  
 2015-10-05 23:19:31,740 | INFO | pool-25-thread-1 | TimerTaskExecutor        | 64 - org.apache.servicemix.bundles.spring-context - 3.2.14.RELEASE_1 | Initializing Timer  
 2015-10-05 23:19:31,839 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.springframework.context.support/3.1.4.RELEASE  
 2015-10-05 23:19:31,841 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.servicemix.bundles.spring-tx/3.2.14.RELEASE_1  
 2015-10-05 23:19:31,842 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.karaf.deployer.spring/4.0.1  
 2015-10-05 23:19:31,854 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.servicemix.bundles.spring-context-support/3.2.14.RELEASE_1  
 2015-10-05 23:19:31,856 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.karaf.bundle.springstate/4.0.1  
 2015-10-05 23:19:31,916 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.camel.camel-catalog/2.15.3  
 2015-10-05 23:19:31,922 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.camel.camel-spring/2.15.3  
 2015-10-05 23:19:31,939 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.camel.camel-core/2.15.3  
 2015-10-05 23:19:31,943 | INFO | pool-25-thread-1 | Activator            | 53 - org.apache.camel.camel-core - 2.15.3 | Camel activator starting  
 2015-10-05 23:19:31,982 | INFO | pool-25-thread-1 | Activator            | 53 - org.apache.camel.camel-core - 2.15.3 | Camel activator started  
 2015-10-05 23:19:32,007 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.camel.camel-commands-core/2.15.3  
 2015-10-05 23:19:32,012 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  stax2-api/3.1.4  
 2015-10-05 23:19:32,014 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  woodstox-core-asl/4.4.1  
 2015-10-05 23:19:32,051 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.geronimo.specs.geronimo-jta_1.1_spec/1.1.1  
 2015-10-05 23:19:32,054 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.servicemix.bundles.jaxb-impl/2.2.6.1  
 2015-10-05 23:19:32,056 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 |  org.apache.camel.karaf.camel-karaf-commands/2.15.3  
 2015-10-05 23:19:32,315 | INFO | pool-25-thread-1 | FeaturesServiceImpl       | 8 - org.apache.karaf.features.core - 4.0.1 | Done.  
 2015-10-05 23:20:53,179 | INFO | nsole user karaf | ultOsgiApplicationContextCreator | 77 - org.springframework.osgi.extender - 1.2.1 | Discovered configurations {osgibundle:/META-INF/spring/*.xml} in bundle [camel-example-osgi (camel-example-osgi)]  
 2015-10-05 23:20:53,219 | INFO | ExtenderThread-1 | OsgiBundleXmlApplicationContext | 64 - org.apache.servicemix.bundles.spring-context - 3.2.14.RELEASE_1 | Refreshing OsgiBundleXmlApplicationContext(bundle=camel-example-osgi, config=osgibundle:/META-INF/spring/*.xml): startup date [Mon Oct 05 23:20:53 MYT 2015]; root of context hierarchy  
 2015-10-05 23:20:53,262 | INFO | ExtenderThread-1 | OsgiBundleXmlApplicationContext | 64 - org.apache.servicemix.bundles.spring-context - 3.2.14.RELEASE_1 | Application Context service already unpublished  
 2015-10-05 23:20:53,325 | INFO | ExtenderThread-1 | XmlBeanDefinitionReader     | 63 - org.apache.servicemix.bundles.spring-beans - 3.2.14.RELEASE_1 | Loading XML bean definitions from URL [bundle://82.0:0/META-INF/spring/camelContext.xml]  
 2015-10-05 23:20:53,611 | INFO | ExtenderThread-1 | CamelNamespaceHandler      | 54 - org.apache.camel.camel-spring - 2.15.3 | OSGi environment detected.  
 2015-10-05 23:20:54,970 | INFO | ExtenderThread-1 | WaiterApplicationContextExecutor | 77 - org.springframework.osgi.extender - 1.2.1 | No outstanding OSGi service dependencies, completing initialization for OsgiBundleXmlApplicationContext(bundle=camel-example-osgi, config=osgibundle:/META-INF/spring/*.xml)  
 2015-10-05 23:20:55,034 | INFO | ExtenderThread-2 | DefaultListableBeanFactory    | 63 - org.apache.servicemix.bundles.spring-beans - 3.2.14.RELEASE_1 | Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@69f2fae4: defining beans [template,consumerTemplate,camel-1:beanPostProcessor,camel-1,myTransform]; root of factory hierarchy  
 2015-10-05 23:20:55,302 | INFO | ExtenderThread-2 | OsgiSpringCamelContext      | 53 - org.apache.camel.camel-core - 2.15.3 | Apache Camel 2.15.3 (CamelContext: camel-1) is starting  
 2015-10-05 23:20:55,304 | INFO | ExtenderThread-2 | ManagedManagementStrategy    | 53 - org.apache.camel.camel-core - 2.15.3 | JMX is enabled  
 2015-10-05 23:20:55,651 | INFO | ExtenderThread-2 | OsgiSpringCamelContext      | 53 - org.apache.camel.camel-core - 2.15.3 | AllowUseOriginalMessage is enabled. If access to the original message is not needed, then its recommended to turn this option off as it may improve performance.  
 2015-10-05 23:20:55,651 | INFO | ExtenderThread-2 | OsgiSpringCamelContext      | 53 - org.apache.camel.camel-core - 2.15.3 | StreamCaching is not in use. If using streams then its recommended to enable stream caching. See more details at http://camel.apache.org/stream-caching.html  
 2015-10-05 23:20:55,742 | INFO | ExtenderThread-2 | OsgiSpringCamelContext      | 53 - org.apache.camel.camel-core - 2.15.3 | Route: route1 started and consuming from: Endpoint[timer://myTimer?fixedRate=true&period=2000]  
 2015-10-05 23:20:55,745 | INFO | ExtenderThread-2 | OsgiSpringCamelContext      | 53 - org.apache.camel.camel-core - 2.15.3 | Total 1 routes, of which 1 is started.  
 2015-10-05 23:20:55,752 | INFO | ExtenderThread-2 | OsgiSpringCamelContext      | 53 - org.apache.camel.camel-core - 2.15.3 | Apache Camel 2.15.3 (CamelContext: camel-1) started in 0.444 seconds  
 2015-10-05 23:20:55,759 | INFO | ExtenderThread-2 | OsgiBundleXmlApplicationContext | 64 - org.apache.servicemix.bundles.spring-context - 3.2.14.RELEASE_1 | Publishing application context as OSGi service with properties {org.springframework.context.service.name=camel-example-osgi, Bundle-SymbolicName=camel-example-osgi, Bundle-Version=2.15.3}  
 2015-10-05 23:20:55,775 | INFO | ExtenderThread-2 | ContextLoaderListener      | 77 - org.springframework.osgi.extender - 1.2.1 | Application context successfully refreshed (OsgiBundleXmlApplicationContext(bundle=camel-example-osgi, config=osgibundle:/META-INF/spring/*.xml))  
 2015-10-05 23:20:56,759 | INFO | timer://myTimer | MyTransform           | 82 - camel-example-osgi - 2.15.3 | >>>> SpringDSL set body: Mon Oct 05 23:20:56 MYT 2015  
 2015-10-05 23:20:56,766 | INFO | timer://myTimer | ExampleRouter          | 53 - org.apache.camel.camel-core - 2.15.3 | Exchange[ExchangePattern: InOnly, BodyType: String, Body: SpringDSL set body: Mon Oct 05 23:20:56 MYT 2015]  
 2015-10-05 23:20:58,746 | INFO | timer://myTimer | MyTransform           | 82 - camel-example-osgi - 2.15.3 | >>>> SpringDSL set body: Mon Oct 05 23:20:58 MYT 2015  
 2015-10-05 23:20:58,747 | INFO | timer://myTimer | ExampleRouter          | 53 - org.apache.camel.camel-core - 2.15.3 | Exchange[ExchangePattern: InOnly, BodyType: String, Body: SpringDSL set body: Mon Oct 05 23:20:58 MYT 2015]  
 2015-10-05 23:21:00,746 | INFO | timer://myTimer | MyTransform           | 82 - camel-example-osgi - 2.15.3 | >>>> SpringDSL set body: Mon Oct 05 23:21:00 MYT 2015  
 2015-10-05 23:21:00,747 | INFO | timer://myTimer | ExampleRouter          | 53 - org.apache.camel.camel-core - 2.15.3 | Exchange[ExchangePattern: InOnly, BodyType: String, Body: SpringDSL set body: Mon Oct 05 23:21:00 MYT 2015]  
 2015-10-05 23:21:02,746 | INFO | timer://myTimer | MyTransform           | 82 - camel-example-osgi - 2.15.3 | >>>> SpringDSL set body: Mon Oct 05 23:21:02 MYT 2015  
 2015-10-05 23:21:02,747 | INFO | timer://myTimer | ExampleRouter          | 53 - org.apache.camel.camel-core - 2.15.3 | Exchange[ExchangePattern: InOnly, BodyType: String, Body: SpringDSL set body: Mon Oct 05 23:21:02 MYT 2015]  
 2015-10-05 23:21:04,745 | INFO | timer://myTimer | MyTransform           | 82 - camel-example-osgi - 2.15.3 | >>>> SpringDSL set body: Mon Oct 05 23:21:04 MYT 2015  
 2015-10-05 23:21:04,746 | INFO | timer://myTimer | ExampleRouter          | 53 - org.apache.camel.camel-core - 2.15.3 | Exchange[ExchangePattern: InOnly, BodyType: String, Body: SpringDSL set body: Mon Oct 05 23:21:04 MYT 2015]  
 2015-10-05 23:21:06,745 | INFO | timer://myTimer | MyTransform           | 82 - camel-example-osgi - 2.15.3 | >>>> SpringDSL set body: Mon Oct 05 23:21:06 MYT 2015  
 2015-10-05 23:21:06,746 | INFO | timer://myTimer | ExampleRouter          | 53 - org.apache.camel.camel-core - 2.15.3 | Exchange[ExchangePattern: InOnly, BodyType: String, Body: SpringDSL set body: Mon Oct 05 23:21:06 MYT 2015]  
   
 karaf@root()>  

and if you list again on the bundle, there are multiple instances running.

 karaf@root()> bundle:list  
 START LEVEL 100 , List Threshold: 50  
 ID | State | Lvl | Version | Name  
 -----------------------------------------------------------------------  
 51 | Active | 80 | 2.15.3 | camel-catalog  
 52 | Active | 80 | 2.15.3 | camel-commands-core  
 53 | Active | 80 | 2.15.3 | camel-core  
 54 | Active | 80 | 2.15.3 | camel-spring  
 55 | Active | 80 | 2.15.3 | camel-karaf-commands  
 56 | Active | 80 | 1.1.1  | geronimo-jta_1.1_spec  
 61 | Active | 80 | 2.2.6.1 | Apache ServiceMix :: Bundles :: jaxb-impl  
 80 | Active | 80 | 3.1.4  | Stax2 API  
 81 | Active | 80 | 4.4.1  | Woodstox XML-processor  
 82 | Active | 80 | 2.15.3 | camel-example-osgi  
 karaf@root()>   

Just like docker contaianer, you can stop and uninstall the bundle and then exit apache karaf.

 karaf@root()> bundle:stop camel-example-osgi  
 karaf@root()> bundle:uninstall camel-example-osgi  
 karaf@root()> bundle:list  
 START LEVEL 100 , List Threshold: 50  
 ID | State | Lvl | Version | Name  
 -----------------------------------------------------------------------  
 51 | Active | 80 | 2.15.3 | camel-catalog  
 52 | Active | 80 | 2.15.3 | camel-commands-core  
 53 | Active | 80 | 2.15.3 | camel-core  
 54 | Active | 80 | 2.15.3 | camel-spring  
 55 | Active | 80 | 2.15.3 | camel-karaf-commands  
 56 | Active | 80 | 1.1.1  | geronimo-jta_1.1_spec  
 61 | Active | 80 | 2.2.6.1 | Apache ServiceMix :: Bundles :: jaxb-impl  
 80 | Active | 80 | 3.1.4  | Stax2 API  
 81 | Active | 80 | 4.4.1  | Woodstox XML-processor  
 karaf@root()>   
 karaf@root()> system:shutdown  
 Confirm: halt instance root (yes/no): yes  
 karaf@root()>   
   

In this article, we are just going through the surface on what apache karaf can do and it certainly deliver! If you are looking for docker container alternative, apache karaf certainly worth the time to look into. Hence forth I think these links will provide you further learning experience.

http://liquid-reality.de/display/liquid/Karaf+Tutorials

https://karaf.apache.org/manual/latest/users-guide/