Ditch commons-codec in favour of Guava.
List the minimum maven version.

This is the minimum version required by the plugins in use.
Anchor the default implicit plugin versions.
Upgrade to the current version of Surefire: 2.16
Upgrade to the current version of the JAR plugin: 2.4
Upgrade to the current version of the compiler plugin: 3.1
Upgrade to the current version of the source plugin: 2.2.1
Drop an unused dependency: asm
Upgrade to current version of JUnit: 4.11
Update to current version of XStream: 1.4.7.
Update to current version of IPResource: 1.46
Update to current version of Mockito: 1.9.5
Update to current version of Log4J: 1.2.17
Update to current version of JODA: 2.3
Update to the current version of the SLF4J API: 1.7.6
Update to the current version of the SLF4J/Log4g adapter: 1.7.6
Simplify this code by calculating the digest without an intermediate bytestream.
Use Guava's closer instead of commons-io's closeQuietly.

The closeQuietly can suppress exceptions that should be reported.
Use Guava's singleton NullOutputStream.
Switch to the Guava way of slurping an input stream into a string.