End-of-line characters conversion between Windows and Linux

Just started to work for a project where the majority of the people use Windows. Quick fix for ^M occuring in shell scripts:

sudo aptitude install tofrodos

and then

find . -name '*.sh' | xargs dos2unix -d

(could be with exec, but for a small number of files it does not really matter)

A cryptographic hash of an empty byte array does exist. Honestly.

An hour or so spent and finally the reason found - no data. That test proves it in a way:

    @Test
    public void testNullDigest() throws Exception {
        MessageDigest md = MessageDigest.getInstance("SHA1");
        System.out.println(ArrayUtils.toString(md.digest(new byte[0])));
    }

The output:

{-38,57,-93,-18,94,107,75,13,50,85,-65,-17,-107,96,24,-112,-81,-40,7,9}

Exactly the same as the one I was getting. In particular, different from the expected one (suprise). I should make some constant ;-/

Quick search in Midnight Commander

Just press Alt+s and then start typing the name.

Prune unnecessary log4j dependencies in maven

If you want to use the newest log4j with maven build, you may notice a few dependencies you may not want to include if you just want to have plain ordinary logging without JMX or mail support.

<dependency>
 <groupId>log4j</groupId>
 <artifactId>log4j</artifactId>
 <version>1.2.15</version>
 <exclusions>
  <exclusion>
   <groupId>javax.jms</groupId>
   <artifactId>jms</artifactId>
  </exclusion>
  <exclusion>
   <groupId>javax.mail</groupId>
   <artifactId>mail</artifactId>
  </exclusion>    
  <exclusion>
   <groupId>com.sun.jdmk</groupId>
   <artifactId>jmxtools</artifactId>
  </exclusion>
  <exclusion>
   <groupId>com.sun.jmx</groupId>
   <artifactId>jmxri</artifactId>
  </exclusion>    
 </exclusions>
</dependency>