Elasticsearch, a Java-based search and analytics engine built on Apache Lucene, relies on the Java Virtual Machine (JVM) for its operation across various platforms. The JVM abstracts the underlying operating system and hardware, enabling Java applications to run platform-independently, while handling crucial tasks such as memory management and garbage collection. The blog emphasizes understanding JVM memory management and troubleshooting issues like java.lang.OutOfMemoryError through garbage collection processes, including the transition of objects between the young and old generations in heap memory. Elasticsearch now uses the Garbage-First (G1) garbage collector for improved performance over its predecessor, the concurrent mark sweep (CMS) garbage collector. Administrators can monitor JVM states and memory metrics using Elasticsearch APIs or the jstat tool for real-time JVM statistics. The blog advises against altering default JVM settings without consulting Elastic Support, highlighting that these defaults are generally sufficient for most use cases. Further insights and potential tuning of JVM settings will be discussed in subsequent posts.