POM is
The issue occurs because the org.geotools:gt-shapefile:jar:10-SNAPSHOT does not exist at either http://download.java.net/maven/2 or http://download.osgeo.org/webdav/geotools. All you have to do is define the snapshot repository for the GeoTools as it is mentioned at the GeoTools:Maven Quick Start as the following: -
maven2-repository.dev.java.net
Java.net repository
http://download.java.net/maven/2
osgeo
Open Source Geospatial Foundation Repository
http://download.osgeo.org/webdav/geotools/
true
opengeo
OpenGeo Maven Repository
http://repo.opengeo.org
I hope this may help.