java - YA ClassNotFoundException involving the URLClassLoader -

after looking through dozens of other questions involving these 2 classes, i've come conclusion might new one.

the code in question involves eclipse (kepler), maven, , geotools - specifically, copy of imagelab tutorial, i've stripped down partially play style classes. changed 1 bit of code create rgb style replace grayscale style example uses - , classnotfoundexception on snippet:

    layer rasterlayer = new gridreaderlayer(reader, rgbstyle); 

if put breakpoint there , step constructor, cnfe on org.geotools.data.featuresource. used class, though, in gt-api jar, , it's downloaded , sitting in maven dependencies folder. in fact, can stick in above line:

    featuresource<?,?> source = null; 

...this compiles happily, , still throws cnfe on constructor after it. finds it, , can't find it??

that cnfe being caught , eaten silently, apparently, if run app without using debug mode - later throws npe when finds layer's style object null.

i've tried restarting eclipse, , running project>clean several times - same problem. gt-api.jar (specifically, gt-api-12-rc1.jar) in build path project. can't step urlclassloader, see it's looking; or @ least, don't know how.

can please explain bizarre behavior, or better, suggest solution? alternately, can tell me how might better @ urlclassloader doing, or thinks classpath is?