After https://github.com/openjdk/jcov/commit/ce686b19c5ae0f3937f7622ee0e5ae50ea32da30

when running ant build, I have all dependencies in JCOV_BUILD:

$ ls build
asm-9.1.jar build.xml networksaver.replace.properties
asm-tree-9.1.jar check-dependecies.xml release.properties
asm-util-9.1.jar filesaver.replace.properties
build.properties javatest.jar

It would be better to put dependencies into a subdirectory, su ah "lib" perhaps.