im4java is a pure-java interface to the ImageMagick commandline. It is not meant as a replacement for JMagick, but as an addition.
im4java is licensed under the LGPL (see file COPYING.LIB). Since im4java is a wrapper libary, you should also make sure that you comply to the individual license-statements of all the tools you use indirectly through im4java.
All documentation is now available in HTML and PDF. Point your browser to doc/index.html. The documentation in the downloaded package usually is a copy of the documentation available on the im4java-website.
Note that the source-distribution only contains the source for the documentation (in doc-src/xdocs).
Any feedback (bug-reports, suggestions, criticism) is welcome. Currently, JMagick and im4java share a single mailing-list. You should register to the jmagick-users mailing-list at jmagick.sourceforge.net.