There is often several scenarios as people have mentioned in former answers. Here are several factors which have served me resolve this. This might be an IDE bug. For example @Joel Costigliola explained a situation where Eclipse did not cope with a Maven "test" tree properly: see this response. (Evidently https://jaredketiv.ttblogs.com/16138209/how-much-you-need-to-expect-you-ll-pay-for-a-good-bongacam-couples