Time series metrics reporting and alerting is an essential tool when it comes to monitoring production services. Graphs help you monitor trends over time, identify spikes in load/latency, identify bottlenecks with constrained resources, etc. Dropwizard Metrics is a great library for collecting metrics and has a lot of features out of the box including various JVM metrics. There are also many third-party library hooks for collections metrics on HikariCP connections pools, Redis client connections, HTTP client connections, and many more.
Once metrics are being collected we need a time series data store as well as a graphing and alerting system to get the most out of our metrics. This example will be utilizing Grafana Cloud which offers cloud-hosted Grafana, a graphing and alerting application that hooks into many data sources, as well as two options for time series data sources Graphite and Prometheus. StubbornJava has public facing Grafana dashboards that will continue to add new metrics as new content is added. Take a look at the StubbornJava Overview dashboard to start with.