New Relic APM is an application performance monitoring (APM) service that lets you see and understand application performance metrics in real time so you can fix problems fast. The Java agent collects system and application metrics by injecting bytecode into a select set of methods. The metrics are reported to the New Relic service once a minute. The agent also reports uncaught exceptions and slow transactions.
The Java Agent installs into your app server and monitors the performance of your apps. The agent monitors applications written in Java, Scala, and other languages that run on the JVM.