When using JUnit inside Eclipse, often times I got unresolved method for assertFalse(). Do you have any idea why? In the beginning I thought there was a clash in JUnit.jar version that shipped with Eclipse. Especially now that JUnit use assertTrue and assertFalse to circumvent 1.4's assert. But funny thing is assertTrue has no problem, I would have thought JUnit will have both assertTrue and assertFalse in the same version. FYI, I was using Eclipse 2.1 for my project.