This is a metabug to track such packages. dev-java/mx4j-3.0.1-r1 uses com.sun.* classes and fails to build with ibm-jdk-bin
jgoodies-looks-2.0.4 uses com.sun.java.swing, fails with kaffe for that
Bug #146946 is about Tomcat and it will be resolved in 6.0.
dev-java/jcharts too
dev-java/exolabcore
games-strategy/triplea-0.9.0.2/
dev-java/xmlgraphics-commons uses com.sun.image.codec.jpeg
All dependent bugs closed now. This makes sense as Java 6 has been dropped.