From my searching, I found supporting information here: Java Development Guide for Mac OS X
tools.jardoes not exist. Classes usually lo
I faced the same problem, and resolved it differently.
/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents and not
/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/HomeAdd the cobertura plugin, make sure systemPath is correctly ref the location of classes.jar
org.codehaus.mojo
cobertura-maven-plugin
2.6
com.sun
tools
1.6
system
${java_home}/Classes/classes.jar
Add the dependency and exclude tools
org.codehaus.mojo
cobertura-maven-plugin
2.6
test
com.sun
tools
Finally add the following profiles
standard-jdk
${java_home}/Home/lib/tools.jar
${java_home}/Home/lib/tools.jar
apple-jdk
${java_home}/Classes/classes.jar
${java_home}/Classes/classes.jar
Now run maven and it should successfully generate the Cobertura reports!