It depends on what you are using it for, “fast” is relative. Java can be fast for applications where performance and scalability are not a primary features. If performance and scalability are core objectives, even performance-engineered Java isn’t really competitive with a systems language. You can bend Java to make it perform better than most people believe, especially today, but the gap is still pretty large in practice.

I wrote performance-engineered Java for years. Even getting it to within 2x worse than performance-engineered C++ took heroic efforts and ugly Java code.