Java performance problems rarely come from "Java being slow" — they come from avoidable patterns that compound at scale. Here's where to focus your optimization effort for real impact.

Profile Before You Optimize

The single biggest performance mistake is optimizing code that isn't actually the bottleneck. Use a profiler (JFR, async-profiler, or VisualVM) to find where time is actually being spent before changing a line of code.

Understand Your Garbage Collector

Different GC algorithms make different tradeoffs between throughput and pause time. G1 is a solid default for most applications; ZGC and Shenandoah are worth evaluating if you're seeing GC pauses impact latency-sensitive workloads.

Watch Your Object Allocation Rate

Excessive short-lived object creation is one of the most common sources of GC pressure. Reusing objects, using primitive collections instead of boxed types, and avoiding unnecessary String concatenation in hot paths all reduce allocation churn.

Use Connection Pooling Correctly

Database connection overhead is a frequent silent performance killer. Ensure your connection pool is sized appropriately for your workload — too small causes contention, too large wastes resources and can overwhelm your database.

Cache Deliberately

Caching is powerful but easy to misuse. Cache expensive, frequently-accessed, rarely-changing data — and always have a clear invalidation strategy before you have a stale-data bug.

Cantonet Technologies performs deep performance audits on Java systems handling high transaction volumes, identifying the specific bottlenecks costing you the most.