Update Sep 2019: The only mocking framework supported (by default) by Spring Boot is Mockito. If you use Spring, the answer is quite obvious. I'd say the competition is between JMockit and PowerMock, then Mockito. I'd leave "plain" jMock and EasyMock because they use only proxy & CGLIB and do not use Java 5 instrumentation like the newer frameworks. jMock also didn't have a stable release for over
![Comparison between Mockito vs JMockit - why is Mockito voted better than JMockit?](https://cdn-ak-scissors.b.st-hatena.com/image/square/98d6f053a97a87156775f60757c60865d0f2c47d/height=288;version=1;width=512/https%3A%2F%2Fcdn.sstatic.net%2FSites%2Fstackoverflow%2FImg%2Fapple-touch-icon%402.png%3Fv%3D73d79a89bded)