Junit testing

After a long break, recently I came across junit testing. This was when I was helping my team member in writing junit tests and suggested where to start from. Then, there was an issue in running a TestSuite.

The code that I used before is something like below:

import junit.framework.Test;
import junit.framework.TestSuite;

public class AllTests {

public static Test suite() {
TestSuite suite = new TestSuite("Test for something");
suite.addTestSuite(SomeClass.class);
return suite;
}
}


But, when i tried to run, I got below error:
java.lang.Exception: No runnable methods

By the way, this is with junit-4. So, here is what we figured out -
In junit-4, they use annotations for TestSuite. So, the old syntax is not working. Here is working syntax

import org.junit.runner.RunWith;
import org.junit.runners.Suite;
@RunWith(Suite.class)
@Suite.SuiteClasses( { SomeClass.class})

public class AllTests {
}

So simple. Isn't it?
Also, download junit coverage plugin for eclipse using this update site http://update.eclemma.org/ . More details are here regarding eclemma

Handling "Ctrl+C" in Java

It is very simple. One just need to use addShutdownHook method and pass a thread where you can add code to do what ever you wanted to.
Sample code is here -

public class ShutdownHookDemo {

public static void main(String[] args)
{
Runtime.getRuntime().addShutdownHook(new Thread() {
public void run()
{
System.out.println("Ctrl+C was pressed by some one and I am exiting now");
}
});

int i = 0;
while(true)
{
System.out.println("I value:" + i++);
System.out.println("Going to sleep now for 2 secs");
try{
Thread.currentThread().sleep(2000);
}
catch(InterruptedException ie)
{
System.out.println("Someone woke me up:("+ ie);
ie.printStackTrace();
}
}
}
}

So simple it is.. isn't it? and I just realized that hadoop used it to close files opened when some one press "ctrl+C". Just one sentence to describe it "Simple yet powerful."

Confused in Java

I had a code where I was using writeBytes() method of DataOutput for writing a string to file. And, it created some issues while reading. Then, I replaced the same with write(str.getBytes()). This went fine without causing any issue. Confused now on what is the difference between these two methods. Still exploring...