how to debug remote cassandra with eclipse

This tutorial is written such a way you install cassandra using debian package and want to debug remote apache cassandra instance with another workstation with eclipse install. With that said, let's start.

* uncomment the following lines in this cassandra environment file /etc/cassandra/cassandra-env.sh . The cassandra environment for debian is located at the path specified.

 # JVM_OPTS="$JVM_OPTS -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=1414"  

* restart apache cassandra instance and verify the above jvm options are shown in ps output.

 $ ps aux | grep cassandra | grep --color 1414  
 cassand+ 26718 44.8 29.8 1556048 1232024 ?   SLl 19:19  2:28 /usr/lib/jvm/jdk1.8.0_45//bin/java -XX:+UseParNewGC -XX:+UseConcMarkSweepGC -XX:+CMSParallelRemarkEnabled -XX:SurvivorRatio=8 -XX:MaxTenuringThreshold=1 -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly -XX:CMSWaitDuration=10000 -XX:+CMSParallelInitialMarkEnabled -XX:+CMSEdenChunksRecordAlways -XX:+CMSClassUnloadingEnabled -Xms1024M -Xmx1024M -Xmn200M -ea -Xss256k -XX:+AlwaysPreTouch -XX:-UseBiasedLocking -XX:StringTableSize=1000003 -XX:+UseTLAB -XX:+ResizeTLAB -XX:+PerfDisableSharedMem -XX:CompileCommandFile=/etc/cassandra/hotspot_compiler -javaagent:/usr/share/cassandra/lib/jamm-0.3.0.jar -XX:+UseThreadPriorities -XX:ThreadPriorityPolicy=42 -XX:+HeapDumpOnOutOfMemoryError -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=1414 -Djava.net.preferIPv4Stack=false -Dcassandra.jmx.local.port=7199 -XX:+DisableExplicitGC -Djava.library.path=/usr/share/cassandra/lib/sigar-bin -Dlogback.configurationFile=logback.xml -Dcassandra.logdir=/var/log/cassandra -Dcassandra.storagedir=/var/lib/cassandra -Dcassandra-pidfile=/var/run/cassandra/cassandra.pid -cp /etc/cassandra:/usr/share/cassandra/lib/ST4-4.0.8.jar:/usr/share/cassandra/lib/airline-0.6.jar:/usr/share/cassandra/lib/antlr-runtime-3.5.2.jar:/usr/share/cassandra/lib/asm-5.0.4.jar:/usr/share/cassandra/lib/cassandra-driver-core-3.0.0-beta1-bb1bce4-SNAPSHOT-shaded.jar:/usr/share/cassandra/lib/commons-cli-1.1.jar:/usr/share/cassandra/lib/commons-codec-1.2.jar:/usr/share/cassandra/lib/commons-lang3-3.1.jar:/usr/share/cassandra/lib/commons-math3-3.2.jar:/usr/share/cassandra/lib/compress-lzf-0.8.4.jar:/usr/share/cassandra/lib/concurrentlinkedhashmap-lru-1.4.jar:/usr/share/cassandra/lib/disruptor-3.0.1.jar:/usr/share/cassandra/lib/ecj-4.4.2.jar:/usr/share/cassandra/lib/guava-18.0.jar:/usr/share/cassandra/lib/high-scale-lib-1.0.6.jar:/usr/share/cassandra/lib/jackson-core-asl-1.9.2.jar:/usr/share/cassandra/lib/jackson-mapper-asl-1.9.2.jar:/usr/share/cassandra/lib/jamm-0.3.0.jar:/usr/share/cassandra/lib/javax.inject.jar:/usr/share/cassandra/lib/jbcrypt-0.3m.jar:/usr/share/cassandra/lib/jcl-over-slf4j-1.7.7.jar:/usr/share/cassandra/lib/jgrapht-core-0.9.1.jar:/usr/share/cassandra/lib/jna-4.0.0.jar:/usr/share/cassandra/lib/joda-time-2.4.jar:/usr/share/cassandra/lib/json-simple-1.1.jar:/usr/share/cassandra/lib/libthrift-0.9.2.jar:/usr/share/cassandra/lib/log4j-over-slf4j-1.7.7.jar:/usr/share/cassandra/lib/logback-classic-1.1.3.jar:/usr/share/cassandra/lib/logback-core-1.1.3.jar:/usr/share/cassandra/lib/lz4-1.3.0.jar:/usr/share/cassandra/lib/metrics-core-3.1.0.jar:/usr/share/cassandra/lib/metrics-logback-3.1.0.jar:/usr/share/cassandra/lib/netty-all-4.0.23.Final.jar:/usr/share/cassandra/lib/ohc-core-0.4.2.jar:/usr/share/cassandra/lib/ohc-core-j8-0.4.2.jar:/usr/share/cassandra/lib/reporter-config-base-3.0.0.jar:/usr/share/cassandra/lib/reporter-config3-3.0.0.jar:/usr/share/cassandra/lib/sigar-1.6.4.jar:/usr/share/cassandra/lib/slf4j-api-1.7.7.jar:/usr/share/cassandra/lib/snakeyaml-1.11.jar:/usr/share/cassandra/lib/snappy-java-1.1.1.7.jar:/usr/share/cassandra/lib/stream-2.5.2.jar:/usr/share/cassandra/lib/thrift-server-0.3.7.jar:/usr/share/cassandra/apache-cassandra-3.0.0.jar:/usr/share/cassandra/apache-cassandra-thrift-3.0.0.jar:/usr/share/cassandra/apache-cassandra.jar:/usr/share/cassandra/stress.jar: -XX:HeapDumpPath=/var/lib/cassandra/java_1473247174.hprof -XX:ErrorFile=/var/lib/cassandra/hs_err_1473247174.log org.apache.cassandra.service.CassandraDaemon# JVM_OPTS="$JVM_OPTS -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=1414"  

* okay looks good, now let's move on to the eclipse. See the screenshot below, connect to it. To get to the debu configuration window, click on 'Run' in the menu, 'Debug Configurations...' on the pop up window, right click 'Remote Java Application' and click new.

* check in the machine that run cassandra instance.

 user@workstation:~$ sudo netstat -tupan | grep 1414  
 tcp    0   0 10.0.0.2:1414    10.0.0.3:60122   ESTABLISHED 26718/java   

That's it! When you are done, remember to terminate the debug process.

Speed up android emulator startup in eclipse

When exploring hello world android development app in eclipse, the emulator just painfully slow to even launch. To me, the speed matter because if it is slow, the test and development cycle will be affected and thus, the development experience will not be pleasant. So today, before we go into hello world article, we will first explore if it is possible to improve the speed of android emulator startup in eclipse.

I have google and found a few links, there are as of following.

• https://software.intel.com/en-us/android/articles/speeding-up-the-android-emulator-on-intel-architecture


• http://stackoverflow.com/questions/1554099/why-is-the-android-emulator-so-slow


• http://www.developer.com/ws/android/development-tools/supercharge-your-android-emulator-speed-with-intel-emulation-technologies.html


• http://askubuntu.com/questions/283972/how-to-speed-up-the-android-emulator-in-ubuntu-12-10


• http://techtach.com/2014/05/boost-android-emulator-performanceon-linux-speeding-up-android-emulator-on-ubuntu/


• http://delphi.org/2013/11/8-tips-to-speed-up-your-android-arm-emulator-avd/


• https://www.virag.si/2012/10/speeding-up-android-emulator/


• http://ubuntuforums.org/showthread.php?t=2160567


• https://www.infinum.co/the-capsized-eight/articles/is-your-android-emulator-just-too-slow


• http://blogs.nuxeo.com/development/2011/10/speeding-up-the-android-emulator/

To summarize the solution used to the links above, there are Intel Hardware Accelerated Execution Manager (HAXM), linux kvm or virtualbox, android virtual device (AVD) snapshot, increase device ram, GPU acceleration, disable antivirus ?!, 3rd party android emulator, using actual android device instead of emulator, etc.

Because every developer has different development environment and every sdk and improvement over time may render these method describe later in this article invalid. Thus, the speed gain in your environment when android emulator start may vary and thus create unnecessary confusion. Thus, you should always read on the links and find a solution that work best in your environment. The following steps improved my environment in such a way.

1. Before it start need 10minutes and then even after waited 10minutes, then it crashed. With this, on my i3 intel cpu, with 8GB of ram, the speed increase in within less than 2minutes and response is emulator is manageable.


2. The emulator start over time is persistence. There are situation when once the android virtual device is created, the second time it boot, the android screen in the emulator get gibberish and unclickable. So with my method describe later, this will not be a problem.

Before we go into the solution, let's understand what emulator is. Emulator according to wikipedia

In computing, an emulator is hardware or software or both that duplicates (or emulates) the functions of one computer system (the guest) in another computer system (the host), different from the first one, so that the emulated behavior closely resembles the behavior of the real system (the guest).

In android sense, this emulator actually emulate a smartphone environment including hardware instruction, from workstation cpu x86 to the android device which uses arm. Because of Android Emulator emulates a real ARM processor on top of an x86 processor, this create a lot of overhead. Connection of real device through usb via eclipse integration is not available for linux environment. Thus, for initial learning phase, a android emulator is a good start.



Launch Android Virtual Device Manager from eclipse.



create a new android virtual device, as seem below with this setting.



As you can see, the target for the application is being currently latest at Android 5.0 - API Level 21. The important part now is to choose CPU/ABI to Intel Atom(x86_64). Of cause smartphone device mostly with arm cpu but as mentioned previously, we want emulator be a quick test environment.

If you notice, I have left Use Host GPU uncheck. When this is check with my environment, there is no speed up and when the android evironment started, the colour became gibberish and not clickable. Now start the device and experience the clicking in the environment.

Happy develop in android.

 

Setting up eclipse with Android development environment

Today, we will explore something different. Android is a very well known brand in the public now and can be found in devices such as smartphone, tablet, wearable like watch and glass, any end user device like tv or smart appliances. So we will take a look from programming point of view. This is a fresh start article and if you come from java development background and has zero knowledge on android development then this is an article for you. More on android development articles will come later.

To reduce the learning curve and to have a better learning and development experience in android, you should really setup android developer toolkit plugin in an IDE. If you have been develop Java for sometime now, IDE such as eclipse or netbeans should come in mind. Eclipse has always been my favourite IDE for java development and in this article, I will share on how to install ADT plugin in eclipse for android environment.

This article is based on this instruction. You should refer that for any changes or error encountered if you read this article in the future. As of this writing, I'm using eclipse luna for this ADT plugin installation. Let's start the installation.

1. Launch eclipse and click Help then Install New Software... then click on Add button.


2. We will add ADT plugin repository to this eclipse IDE. In the pop up window, add as following and then click on OK.
   Name: ADT Plugin
   Location: https://dl-ssl.google.com/android/eclipse/
   


3. Wait a while for the update to pull in by eclipse and the in the Available Software dialog, select the checkbox next to Developer Tools and click on Next.
   


4. In the next window, you'll see a list of the tools to be downloaded. Click Next.


5. Read and accept the license agreements, then click Finish.
   If you get a security warning saying that the authenticity or validity of the software can't be established, click OK.


6. When the installation completes, restart Eclipse.


7. Once Eclipse restarts, you must specify the location of your Android SDK directory. Because this is a new installation, there is no android sdk installed and click on Open Preferences.
   


8. In the "Welcome to Android Development" window that appears, select Install new SDK. Then wait until the installation is complete.
   
   


9. When sdk is installed, a new window popup requesting to install new build tool. Click on Open SDK Manager.
   


10. There are preselected build-tools and as of this moment, just accept the default preselected tools and click Install button. We can install more tools later.
    


11. Wait until the installation is complete and it is done.

That's it, now start the first session for android hello world development.

Lightweight Java Game Library

Since childhood, gaming has been one of my favorite activities. If you are from 80s, Supermario should sound familiar to you. =) 30 years had passed, gaming development improve tremendously over the period.

In this article, we are going to explore gaming development. Most of the gaming is written in low level languages, example C and thus, it is very complicated. This certainly introduced steep learning curve if you are a beginner. Hence, we will choose a simple startup to learn about gaming development. A example of library that can be use is Lightweight Java Game Library or its acronym LWJGL.

What is Lightweight Java Game Library?

The Lightweight Java Game Library (LWJGL) is a solution aimed directly at professional and amateur Java programmers alike to enable commercial quality games to be written in Java. LWJGL provides developers access to high performance crossplatform libraries such as OpenGL (Open Graphics Library), OpenCL (Open Computing Language) and OpenAL (Open Audio Library) allowing for state of the art 3D games and 3D sound. Additionally LWJGL provides access to controllers such as Gamepads, Steering wheel and Joysticks. All in a simple and straight forward API.

Because nature of this library deal with graphic display, hence the hardware display driver must be setup correctly. For me, my workstation is using ati radeon, and using xserver-xorg-video-radeon and enable 3D acceleration with package libgl1-mesa-dri. We won't delve deep into graphic driver installation and configuration since our focus here is the gaming development. You can check if your drive is setup properly by running glxgears via a terminal. If a windows popup with three gears spinning, your driver install and setup should be fine to continue for this coding tutorial.

In the official wiki, it is well written and documented to get you started. With this, I have setup my eclipse environment in debian sid. The library needed to should be setup in the project build path so when you run your application, the library is detected. Because I'm running linux, the native library location is pointed to lwjgl-2.9.1/native/linux. These two library must be configured before any development begin. If you noticed, I've setup the source as well, it will be convienient to read the code if you need to be sure later down the road during coding phase.



There are many tutorials to pick from, as a start, I just pick the basics - LWJGL Basics 1 (The Display).  The source code should be in the link, and it is incredibly easy to create the display with few lines of codes and I got that window display with just initial try. Very impressive and promising.



It is pretty impressive what this library can do. There are many examples that come in the library and one of it is an example game. Just execute

java -cp .:res:jar/lwjgl.jar:jar/lwjgl_test.jar:jar/lwjgl_util.jar:jar/jinput.jar: -Djava.library.path=native/linux org.lwjgl.examples.spaceinvaders.Game

if you are running linux. Run fine in my environment and played the bundle game; amazing. Maybe in my next article, I'm gonna try to even complete this .