dcm4che and dcm4chee are licensed under an MPL/GPL/LGPL triple license - similar to Mozilla. This allows use of the files under the terms of any one of the Mozilla Public License version 1.1 (MPL), the GNU General Public License version 2 or later (GPL), or the GNU Lesser General Public License version 2.1 or later (LGPL).
Example license block from a source file:
/* **** BEGIN LICENSE BLOCK ****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is part of dcm4che, an implementation of DICOM(TM) in
* Java(TM), hosted at http://sourceforge.net/projects/dcm4che.
*
* The Initial Developer of the Original Code is
* <snip>
* Portions created by the Initial Developer are Copyright (C) 2002-2006
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* <snip>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* **** END LICENSE BLOCK **** */