Cobertura is probably using the wrong .SER file when generating the reports. When you instrument your classes, Cobertura generates a .ser file containing basic information about each class. As your tests run, Cobertura ADDS additional information to this same data file. If the instrumented classes can not find the data file when running then they will create a new one. It is important that you USE the same cobertura.ser file when instrumenting, running, and generating reports.

The best way to do this is to specify the location of the data file when running your tests. You should pass the -Dnet.sourceforge.cobertura.datafile=${BASEDIR}/cobertura.ser sysproperty to the JUnit task.

Another common problem is that the cobertura.ser file is deleted, but the previously instrumented classes are not also deleted. Any time you delete your coverage data file you should also deleted all instrumented classes.

Cobertura is probably using the wrong .ser file when generating the reports. When you instrument your classes, Cobertura generates a .ser file containing basic information about each class. As your tests run, Cobertura adds additional information to this same data file. If the instrumented classes can not find the data file when running then they will create a new one. It is important that you use the same cobertura.ser file when instrumenting, running, and generating reports.

The best way to do this is to specify the location of the data file when running your tests. You should pass the -Dnet.sourceforge.cobertura.datafile=${basedir}/cobertura.ser sysproperty to the JUnit task.

Another common problem is that the cobertura.ser file is deleted, but the previously instrumented classes are not also deleted. Any time you delete your coverage data file you should also deleted all instrumented classes.