Emma - Java Code Coverage Made Easy (Part 2)

This is the second post on Java code coverage with Emma. In previous post, we discussed about Code Coverage and introduction to Emma. In this post, we will discuss about how to install Emma and do the basic code coverage with an example and screenshots. After you complete the reading of this post and previous post, you should be able to download Emma, install it and run Emma from command line. Towards the end, we will also discuss about how to get HTML report and interpret simple Emma report. It will be good if you can download Emma from here and use it side by side as you read this post. Please make sure that you download the binary of Emma and not the source version. The binary version of Emma should be sufficient to do this. Along with this, you need to have Java compiler and Java Runtime Environment to compile your Java classes. In order to give a picture of how Emma works and process involved, let us take the toughest approach of running Emma from command line rather than integrating with IDE. In later posts, we will discuss about IDE integration (Eclipse/Netbeans) to make developers life easier.

Downloading and Installing Emma
Emma comes in three different versions - binaries with examples, source and libraries. In order to do this example, we need to download "binaries with examples and documentation". You can directly download it form Sourceforge.net or you can access Sourceforge project via Emma home page. Irrespective of the way you choose, please make sure that you download Emma binaries with example version. After downloading emma..zip, unzip in a directory. You find three directories "docs", "examples" and "libs". Inside the directory "lib", you will find two JAR files emma.jar and emma_ant.jar. For time being, we will not be requiring emma_ant.jar as it is used to integrate with "ant" which we will cover in subsequent posts. The JAR "emma.jar" is the tool that we will be using throughout this example. Apart from the examples given in this post, you can also try to play with the examples that comes with Emma. Take "emma.jar" from the extracted directory and copy it to the directory where we have our examples. The following picture shows my setup.

Emma.jar and Examples

Java Program Example
Consider the following Java classes. Greater.java is the main class that we are going to test and measure coverage with the help of GreaterTestDriver.java. The class "GreaterTestDriver.java" mimics the testing of the class "Greater.java".

GreaterTestDriver.java

Greater.java

Greater.java has compare method and it prints out the largest of two numbers. GreaterTestDriver.java creates an object of "Greater.java" and invokes compare method passing values 10 and 5 respectively. For values 10 and 5, if block in the method compare is executed and else part will not be executed which our coverage has to pin point.

Running Emma
Running Emma is simple and you only need to specify emma.jar in the classpath and run your application using "emmarun" command. In our case, it is running the test driver "GreaterTestDriver" class. Once you run Emma and after you application exits, Emma prints the coverage results in a text file "converage.txt".

Running Emma and Getting output in text file

If you look at the report "coverage.txt", it gives the coverage data at package, block, method, class and line level.

You can also run Emma and get report in HTML format. Again it is very simple and you need to specify that in command line options (refer the last boxitem to know more about command line options used in this post).

Emma with HTML Reporting

So far you have run Emma and got the HTML report. But the data given by Emma shows the coverage results but the information is not sufficient. It will be helpful to merge the results with source code. Emma can also pin point which lines are executed and which lines are not executed. Yet again, the step is simple and following example is self explanatory.

Emma Reporting with Source Code

In the above report, the lines that are highlighted in green color are the ones that are tested at least once and the lines that are in pink color are not tested. In ideal case, you need to improve your test suite to cover the lines that are highlighted in pink color. As an exercise, can you achieve 100% coverage in Greater.java?

Command options used in this example

# In order to run Emma from command line and to get report in test file

java -cp emma.jar emmarun -cp . example.GreaterTestDriver

# In order to run Emma from command line and get report in HTML but without Source Code

java -cp emma.jar emmarun -r html -cp . example.GreaterTestDriver

# In order to run Emma from command line, get report in HTML and merge the result with Source Code

java -cp emma.jar emmarun -sp . -r html -cp . example.GreaterTestDrive

In this post we saw only on-the-fly instrumentation and in upcoming posts we will discuss other features of Emma such as Eclipse (and Netbeans) integration, off-line instrumentation, integrating with ant and merging data of multiple sessions, integrating with Tomcat.

I have also come up with a little interactive presentation with flash using Wink on Emma. It can be accessed through this link

Hotswap Agent for Java Virtual Machine (Part 1)

Before joining my company and in fact until two years after I joined my company, C, 8085/8086 ALP and Perl are the programming languages I knew. I learned C and ALP at college and Perl at my office to write a simple CGI utility. Two years later, I started to learn Java as I was moved to development team and I started to learn Java with certain amount of dislike. After a short period of time, I started to read about Java Virtual Machine specification and writing tools with the help of JPDA. Writing tools using JDI/JPDA is relatively simple as JPDA gives you enough infrastructure. This post contains specification/requirements for writing a small and powerful agent to reload classes of live JVM. As you may know, Java source code is compiled and bytecodes are produced. These bytecodes (generally .class files) are loaded into JVM and are much like machine instruction but the fact is that only JVM can understand it. These bytecodes are your program and decides how your application is executed.

If you are a developer, your daily job might be writing code or fixing bugs or both. During development, you may need to change the logic of your program, recompile the source and restart the application. Restarting the application is stopping the running JVM and starting a new JVM process. This is a very lengthly process if your work involves changes to source code multiple times. Sun HotSpot VM comes with a feature called HotSwap. Using this feature one can replace the classes that are loaded in the JVM. Once reloaded, the objects that are already created also takes effect with new changes. This tool will improve the productivity of developers when frequent restart of the applications is required. Here is the specification.

Specification

Write a simple tool which let you to reload classes in a running JVM without restarting your application. Also provide a simple user interface (probably using SWING).

Steps

1. Use Java Debug Interface API to connect to remote JVM. In order to connect to remote JVM, you the hostname/ip address of the remote box and port number on which your JVM runs. In order to hotswap the classes, you need start JVM in debug mode and if you start JVM using "socket" debugger.

2. Also subscribe for few important events such as JVM Exit, Disconnect Event. (for more info refer Java Debug Interface API Spec).

3. If the connection is successful, you get an instance of the remote JVM and you can once again use JDI to replace classes.

4. You have to write the logic of reading the class file (flat file) from the file system and give to JDI. JDI pumps the class file to remote JVM which reloads the class after making lot of checks.

In next couple of days, I m planning to write a post on how to do this with a small example (thanks to Veeru for pointing this out).

Emma - Java Code Coverage Made Easy (Part 1)

Irrespective of the number of lines of code you write and if you are a good (and honest) tester or developer, you accept the fact that it is impossible to test the entire software. I am not talking about those simple programs like printing "Hello, World". I am talking about software that is decent in size. Testing software is brain intensive. I would like to give you a simple scenario how I used to think when I was in testing team (of course, that was 6 years back when I was fresher). When I was executing a test case or writing a test case, I generally used to get few parallel thoughts about what are the other related test cases. It never ceases there. It went on and on until I felt comfortable. If I did not cover some corner cases, something would pinch me from inside to do more, to spawn many parallel thoughts and eventually I would end up writing more test cases. While this approach is good, but this is very subjective and depends on the person who is testing. It depends on the knowledge level and expertise of the person who is doing the testing. The testing should be much more and also driven by data. Even if we take that most of the testers of are effective, how are we going to convince and be sure that the test cases are effective?

As a tester, we generally used to get requirements, design documents (?) and finally code in binary format. If you apply general system thinking, tester is above developer simply because he supervises developers' work and validates it. The confidence level of the tester has to impeccable so that the project managers, product managers can have sound sleep and sound sleep every night. This confidence comes with thoroughness of testing and this ability is only possible if you eat, sleep, think with testing in your head and practice testing as art. You might be watching YouTube, but yet you will think like a tester. You might be doing test strategy, test planning, test plan, sophisticated test case design. All these comes in the following ways - requirements, design document, your understanding about how the code will look like and ad hoc testing. But is that sufficient. We are living in the world of doing more and wanting more, testing effectiveness is no exception. Is there a mechanism by which I can measure my test suite effectiveness. Yes, it is there. The rest of the post deals with doing code coverage for Java applications using Emma, an open source code coverage tool.

First, what is code coverage? The process of measuring or seeing which part of code that are tested and the areas that are not at all tested is called code coverage. Second, why is it important? The answer is read the definition again. Period. If you are unit testing you code, it helps you to see the coverage immediately and hence you can fix it "then and there" and butterflies will not fly in your stomach when the product goes to testing team. If you are a tester, it helps you to measure - first your test plan and then the code. Naturally, you will write more test cases or change the existing test cases to cover more. The point is "more coverage". So, no more butterflies in your stomach too when your product goes out to production.

Emma is an open source software which is simple, powerful and flexible. Emma uses bytecode instrumentation technique and measures the code coverage. It has the ability to instrument the classes on-the-fly and also supports offline instrumentation. In on-the-fly instrumentation, you just give the location of your Jar file or class files, Java Virtual Machine when it loads the classes it instruments the logic for code coverage. In offline mode, you need to do an additional step of adding the logic to Jar/class files and copy it in your hard disk and load the instrumented classes to Java Virtual Machine. But irrespective the method you choose, the code coverage will be same. The offline mode is particularly helpful when you have custom classloaders like application servers or servlet container.

You can run Emma directly from command line and you can also integrate with nightly build as a part of continous improvement strategy. Ideally, in nightly build, code coverage works hand in hand with Unit Testing Framework like JUnit. After instrumentation, you have carry out your testing. When you are testing, Emma does the code coverage. Once you are done with the testing, you can safely stop the application. Emma also comes with reporting and it can produce reports in HTML and XML. The report can also be merged along with source code and by just looking at this report, you can identify the lines that not covered.

Apart from running Emma from command line and including with ant, it can also be used at developer's desktop. Emma has plugins for famous IDEs - Eclipse and Netbeans. With this, the developer's can run their unit test cases with Emma immediately after implementing a unit of code. Based on the coverage, they can work on their unit test cases to achieve better coverage. Better coverage, better quality and improved confidence. With this, we come to an end on introducing Emma - Open Source Java Code Coverage Solution.

In the next post, we will be discussing how to install Emma and use it.

Have a Great Day

I have also come up with a little interactive presentation with flash using Wink on Emma. It can be accessed through this link

Speaking Experience @ ILUG Chennai Monthly Meet

This is the first time that I am speaking in Indian Linux User Group, Chennai. ILUG is most active LUGs in India. The meeting generally happens in IIT Madras (the place I wanted to study). Again, I want to reiterate the fact that speaking about Open Source in Open Source meeting gives me enough motivation and abundance of energy. I registered the topics with Mr. Bharathi Subramainan and he gave be slot immediately. Today, I also noticed what happens when people with passion sign up to do something. Unlike other meetings, the members were very punctual and I could see considerable number of people waiting in the hall and some people working in computers in another room. Today's incident enlightened me about valuing others time and I will never forget this in my life. Apart from that we also had good knowledge sharing session.

The talks started at 3.15pm and the first talk was hosted by Selvakumar K from NRC-FOSS on KTechLab, an Open Source IDE for Electronics and PIC Micro Controller Circuit Design and Simulation. He talked about analog and digital simulation tools in Linux. I feel that the tool will help any electronics student to do experiment in his/her laptop/computer. The colleges should seriously consider to have this tool in their department and encourage students to use when they are doing practicals or learning theory.

Next, I started my talk on Java Code coverage and explained about need for code coverage and features of Emma. I talked about various ways of using Emma such as with IDE, nightly build, from command line, online instrumentation and off-line instrumentation. Towards the end, I gave a quick demo on using Emma with Eclipse, on-the-fly instrumentation from command and HTML reporting.

Towards the end, Prof Dr C N Krishnan talked about NRC-FOSS and its Phase 2 initiatives. He requested the help from ILUG-Chennai. He also expressed his concerns on giving feedback to NRC-FOSS.

We have also been given some stickers, pens and Fedora CDs sponsored by Ubuntu and the speakers have been given caps (so, I got one) from Ubuntu. This Saturday was fulfilling and exciting as well. Looking forward for more such knowledge sharing session.

Creating Virtual Machine in VirtualBox - Screenshots

For more than four years, I have been using VMWare workstation and from last year I started to use Virtual Box. Virtual Box is a virtualization product by Sun which virtualize X86 platform and supports Windows, Linux, Solaris and Open Solaris as guest operation system. It is good that Virtual Box is released under open source license and it is available for free of cost. You can download Virtual Box from here. Installing Virtual Box should not take more time and it is very simple like installing any software. Just double click the binary executable and answer few usual questions. You are done. I captured the screenshots of creation of Ubuntu Virtual Machine. One feature, I like about Virtual Box is you can reuse Virtual Disk. We will see this in another post. I am presenting the screenshots that I captured. By following this post, you should be able to create a virtual machine and start installing operating system of your choice.

1. Create New Virtual Machine

2. Click Next in "New VM Wizard"

3. Specify Operating system, distribution and give a name to this VM

4. Specify the virtual RAM size (leave at default)

5. Create a new VM and new virtual disk

6. Click next in "Virtual Disk" Wizard. This is the sub-wizard in the main wizard. If you already created virtual disk, you can skip this setup by choosing virtual disk from available list.

7. Choose virtual disk storage type (leave at default)

8. Specify a name for Virtual Disk and size

9. Click "Finish" to create virtual disk

10. Click "Finish" to create VM. After this step, a new VM should have been created.

11. Open settings and choose either CDROM or ISO file location. So that VM will use CD/ISO for OS installation

12. And finally start the VM. Now VM is ready to install Operating system. From here, VM is as good as physical machine.

In this post, we saw how to create virtual machine. The steps are same irrespective the guest operating system. Virtual Machine behaves much like a physical X86 based system and as of now many flavors are Linux, Windows, BSDs can be installed as guest operating system. Guest operating is the operating system that gets installed in the virtual machine. For example, in a Windows XP system, we can virtualize many virtual machines. The operating that gets installed in the virtual machine is generally called as guest operating system.

Creating a WoW

We, as a human being are like goats. By and large, we go with majority. When so many people in a room say that "world revolves around me", we will also agree with it. If they say, they want to create a wow, all of a sudden and without understanding the science and art of innovation, we will jump in and say "yes, we will". Up to this, it is quite good. At least you have the curiosity. But the worst things is many of us tend to stay in the same place without taking any initiative. We just want to build a marvelous building at this moment without any foundations/hard work. Creating a wow or innovation is easy. But it is not so easy and does not come just like that. I am not a innovator and I have distantly worked with some innovators. Here is my point of view.

Many of us are working on creating wow for others. I don't question the willingness and focus to create wow for the others (mainly customers). But I do like to ask you a question. Have anyone did something for you that impressed you. Otherwise, did anyone in your life created a wow for you. How does a wow smells, what do you feel about it, does it speak to you? When someone did it, did you feel that you were in heaven. Without understanding what a wow is and without even experiencing something, how can you create a wow. Even if you create a wow, how can you say that it is "wow". Creating a wow once or twice is easy and may be gotten due to luck. Do you know how to do it consistently? Do you have the magic of converting the air as wonderful music like a flute.

First of all, may it be innovation or quality or productivity, it sucks without daily improvements. The daily improvements are the foundation. Here my point is not the final product (the big idea) but it is what we do to bring that big idea. The knowledge we gather, the type of people we interact, the number of minutes, hours we think and so on. Without focusing these foundations, creating a wow is just a lip service and I am sure that it is never going to happen. Innovation is a chemical reaction, the reaction that takes place in your brain and you really need to work hard and be consistent in fusing your neural circuit.

Creating wow is not an one time event. We need to come up with techniques where we can create wows like an engine. The customer may not like to stop with just one idea. She wants two, three, and infinite. The ideas are going to give an impression , and it is also true, that you care for her (though it is not the only way to impress). So, if you are consistent, you will be in the game. Else the customer is going to say that you are outdated.

Another thing that we are doing is "ritualize" wow creation rather than internalizing it. When you practice as a ritual, you do it but without involvement, passion and halfheartedly. After internalizing and comprehending it, you do it more with involvement and wholeheartedly. This is another key thing that we need to watch out for.

The final thing is give people the resources and freedom. The resources can be in terms of time and environment that is suitable for creating wow. You cannot expect an idea when people are squeeched and used to maximum possible extent. If you ask a stressed guy, he can only give mediocre ideas. Give them time to think and then expect sparkling ideas.

The above discussed things are my viewpoint. I look forward for your response/comments to learn more on this.

Economic Slowdown - When are going to hit the ground?

It is a trillion dollar question that when are we going to hit the bottom before making a recovery. This is a very hot news and it is minutes after US Fed released minutes. In summary, Fed sees that the economy is deteriorating and downside risk is high. And another point here is the economy is deteriorating more than expected and it is likely that the customers will hold back the spending which again lead to production cuts which leads to lay-offs. This is going to be cyclic and will take sometime to break the cycle and to go in counter direction. In summary, there is lot of downside risk in short term before something happens in a long term

Hold your breath and read through these pages.

Google News
Yahoo News
CNN
Bloomberg

Again, in another two months, the markets are going to see another bottom, may it be capital markets or job market. Now, we should believe someone who says the recovery is going to take three years :-(. Hard truth, but it is truth, we have to digest and move forward.

How to Mount Windows Partition from Linux

I have dual boot in my laptop with Windows XP and my favorite Ubuntu. Windows XP is factory default. Two years back, I installed Fedora and after trying the recent version of Ubuntu, I wanted to install Ubuntu and it has become my favorite in no time. I simply like it. Since I backed up some important Ebooks and documents into Windows partition, I wanted to access those both from Windows XP and Ubuntu. After doing some searching in Internet, I found a mechanism to mount windows partition to Linux.

First, you need to identify the number of Windows partition and locate the partition that you want to mount. "df -k" will help you to identify all the partition/disk in your system. Then, use the "mount" command to mount. For example, here is the sequence of steps to be followed. Run "sudo fdisk -l" and identify windows partition and then mount it using script given after fdisk output.

lnarasim@lnarasim-laptop:~/scripts$ sudo fdisk -l

Disk /dev/sda: 78.5 GB, 78518522880 bytes
255 heads, 63 sectors/track, 9546 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xd0f4738c

Device Boot Start End Blocks Id System
/dev/sda1 * 1 1958 15727603+ 7 HPFS/NTFS
/dev/sda2 1959 9546 60950610 f W95 Ext'd (LBA)
/dev/sda5 1959 4569 20972826 7 HPFS/NTFS
/dev/sda6 4570 4736 1341396 7 HPFS/NTFS
/dev/sda7 4737 4985 2000061 82 Linux swap / Solaris
/dev/sda8 4986 9546 36636201 83 Linux
lnarasim@lnarasim-laptop:~/scripts$

lnarasim@lnarasim-laptop:~/scripts$ cat win_mount.bash
#! /bin/bash

sudo mkdir -p /media/c
sudo mkdir -p /media/d

sudo mount -t ntfs -o nls=utf8,umask=0222 /dev/sda5 /media/c
sudo mount -t ntfs -o nls=utf8,umask=0222 /dev/sda6 /media/d

I have also come up with a simple shell script to do that. If you want, you can also add this in startup scripts so that Windows partition is mounted automatically after startup. With simple use of Linux commands, we are able to access Windows partition.

Absorption and Agility - Learn from Animals

The recent days is testimony for many companies for their absorption capability. There are times when the companies should be agile in looking out opportunities and some times it so happens that they need to tuck their tail and sit idle waiting for opportunities. Sitting idle, as the words suggest, will not yield any benefits other than optimizing the operational costs. I remember that I read that in some business journals that the best companies in the world invest in innovation and making new products which supposed to take chuck of money. Being an uncertain time, many of us fear about the future's prospectus. It greatly applies to individuals also.

There are times when one needs to retreat and practice "wait and watch" game. And sometimes and the situation is in favor, we need to be agile to make use of the opportunity. Few months back, Microsoft's intention to buy Yahoo is an excellent example how things should not be done. Microsoft gave enough time to Yahoo and Yahoo thought that Microsoft undervalued Yahoo. The deal did not go through affecting the stakeholders of Yahoo.

If you ever wonder how to learn "Absorption and Agility", watch this video. We have to learn a lot from animals. Because, they do not have greed like human beings and their agenda is just to survive. I am sure, you will love it.

Lip Service, Laziness and Five Years in Hell

My father was a teacher in state government and he has retired now. When he was in service, he used to go to election booths as presiding officer. When we were kids, he used to tell us about his election experience. There would be so many people inquire him about his election experience on how people stone the election booths. Generally he used to go to other constituency and during all his election duties he never stopped exercising his duty - casting his vote (through post) .My grandmother is now 80s and she never missed one. Check with your family, you will have many great grandparents who are still casting their votes and show us that casting votes is such an important one. But these days, the people are merely enjoying a holiday either watching movies or mini-serial or mega-serial. You have whole bunch of entertainment channels. Also, this time, we also have IPL. Whether it is Congress or BJP or XYZ, why should I bother? Whatever is going to happen is going to happen? I can always yell at politicians or my servant just in case the economy fails.

Sometime back, the senior advocate and journalist Mr Cho. Ramaswamy, in his speech said that people of this generation do not exercise their electoral rights properly. It was proven right during that time that a by-election in TN registered a record polling of 90%. God and politicians only knows how they made the record. Sometimes, even God does not know. When we are not going to exercise our votes, there are two things that can possibly happen. Either someone cast your vote or wrong candidate has been selected to represent you because you did not vote. When you sum up, both the cases is sufficient enough to take our country backwards. If you are going to assume that no one will cast your vote other than you, you are dead wrong. This is secret for record polling. With this economic recession, the prosperity will be evaporated if a wrong party or party with protectionism comes to power. So, use your voting rights to pick the right candidate and right party.

Let us make this place a better one for the future generations. Let the future generations know that their great grandparents are visionaries and thought leaders. If you choose the other way, the next five will be "hell".

Speaking experience @ VIT, Vellore

This is the first time that I am visiting to Vellore and Vellore Institute of Technology. Today, I happen to be there for a talk on Linux Process, POSIX Threads and Linux Scheduler as a part of a workshop on "Open Source Initiatives and Linux Kernel Internals" organized by School of Computing Sciences VIT. I was very fortunate to share the speaking podium along with eminent and highly accomplished Prof. Dr. C N Krishnan and ILUG-C co-coordinator Mr. Bharathi Subramanian. We started in Chennai around 6 am and reached Vellore at 8.30am. The faculty members and Director gave us a warm welcome.

Around 9am, we headed to the auditorium for the workshop. The first part of the workshop is on NRC-FOSS. Dr Krishnan covered the agenda of NRC-FOSS (Phase 1 and Phase 2) and why FOSS makes sense to India. It was insightful and towards the end, I could find many students charged up to take open source in their mainstream learning.

Next, I spoke on Linux Process Management, POSIX Threads and Linux Scheduler. The students were very much interactive and had a lot of enthusiasm to ask questions. I too felt that some questions really made me think. After my talk, Mr. Bharathi took the session on Linux Device Driver and showed how to write simple kernel module and simple dummy character device driver. Again, this talk helped me to refresh whatever I learnt some 3 yrs back.

During the workshop and throughout the day, we received an excellent hospitality from the faculties and students. Overall, it was another productive Saturday and I can sleep with a lot of satisfaction. You can view some of the pictures that are taken during workshop @ here.