🧨 7 Java Anti-Patterns That Look Clean in Code Review… but Silently Destroy Throughput in 2025

Some Java code looks elegant, modern, and “best practice” at first glance — and that’s exactly why it slips past code review.

But under real production load?

🔥 It kills throughput.
🔥 It melts CPU.
🔥 It starves threads.
🔥 It collapses your SLA.

In 2025, with virtual threads, high-core servers, microservices, and low-latency expectations, these anti-patterns are deadlier than ever.

Here are seven patterns that look clean — but silently sabotage your performance.

❌ 1. Synchronized Accessors on Shared Objects

✔ Looks simple.

❌ Performs horribly.

public class UserContext {
    private String token;
public synchronized String getToken() {
        return token;
    }
    public synchronized void setToken(String token) {
        this.token = token;
    }
}

This passes code review easily:

• Simple
• Clear
• Thread-safe