Here are two major types of JVMs:

HotSpot JVM: The most widely used JVM, developed by Oracle. It is known for its performance and features.

OpenJ9 JVM: Developed by IBM, OpenJ9 is another popular option with a focus on low memory footprint and performance.

HotSpot JVM:

  1. Developed by Oracle.
  2. It is the most commonly used JVM, known for its excellent performance, robust just-in-time (JIT) compilation, and advanced garbage collection techniques.
  3. HotSpot optimizes application performance by dynamically compiling code during runtime, allowing for adaptive optimizations based on the code's execution pattern.
  4. Supports a variety of garbage collectors like G1, Parallel GC, and ZGC, each suited for different use cases.

                            hotspot JVM

OpenJ9 JVM:

  1. Developed by IBM and now maintained under the Eclipse Foundation.
  2. OpenJ9 is designed for efficiency with a particular focus on a low memory footprint and startup performance, making it suitable for cloud environments and large-scale enterprise systems.
  3. While it may not offer as many aggressive optimizations as HotSpot in certain workloads, it excels in environments with constrained resources or when rapid startup times are crucial.
  4. OpenJ9 also integrates with OpenJDK and supports modern garbage collection techniques like Balanced GC and Generational GC.

These JVMs are interchangeable, but each has different strengths, depending on the use case.