discriminating libraries like that is one of those skills, imho...
I think having a deep understanding of the most useful libraries is powerful : maven, OSGi, Jetty, ActiveMQ, HttpClient, Hadoop, Velocity, other popular projects on apache, GSON, JUNG, JUnit (in depth)...
I think having a deep understanding of the most useful libraries is powerful : maven, OSGi, Jetty, ActiveMQ, HttpClient, Hadoop, Velocity, other popular projects on apache, GSON, JUNG, JUnit (in depth)...