I have upgraded the Whoola code from COLLADA 1.3 to COLLADA 1.4. You can see demos here:

Whoola Cyberspace -- 3D browser
http://earth.whoola.com:8080/space/cyber/

Whoola COLLADA Converter -- converts to COLLADA format
http://earth.whoola.com:8080/space/collada/

The import/export code works with Xith, an Open Source scene graph renderer for Java:
http://www.xith.org/

The Java source code is available under the terms of an Open Source license from SourceForge.net:
http://whoola.sf.net/

Javadoc for the COLLADA 1.4 Schema converted to Java using JAXB:
http://earth.whoola.com:8080/javadoc/collada/