Oracle Coherence is mature and feature-rich product. However, there are a few old pain points. One pain point is cluster configuration. On complex projects, it is a challenge to consistently maintain custom Coherence XML and the rest of application configuration (often based on a Spring framework). Another pain point is testing. Due to internal implementation, it is impossible to start multiple Coherence nodes in a single JVM without special tricks. Multi-node test setup is important if the application is exploiting advanced features of the product. This is somehow addressed by the community (there are three open-source frameworks for testing Coherence), but the problem could have been solved by Oracle once and for all.
