The framing assumes teams make a clean "pick one" choice, but in my experience the reality is messier. Most enterprises I've worked with end up running both .NE

The framing assumes teams make a clean "pick one" choice, but in my experience the reality is messier. Most enterprises I've worked with end up running both .NET and Java — not because anyone planned it, but because acquisitions, third-party dependencies, and different team preferences make it inevitable. The more interesting question might be: how well does your architecture handle having both? Teams that go all-in on one stack often find themselves 3-5 years later integrating with a Java service they inherited through an acquisition, or needing a .NET library that doesn't have a JVM equivalent. To actually answer the question though: C# and .NET in 2026 are genuinely excellent. The language has evolved faster than Java in many ways (records, pattern matching, LINQ). But Java 21+ has closed the gap significantly with virtual threads, sealed classes, and the continued investment in GraalVM. For a greenfield project, the honest answer is both are fine choices — your team's familiarity matters more than language features at this point. What I wouldn't do is pick a stack purely based on cloud vendor lock-in. That's the one decision that actually limits your future options.