Language runtimes are the execution environments (interpreters, VMs, garbage collectors, standard libraries) that determine how code runs – shaping startup, latency, throughput, memory, and interoperability.

Types and Characteristics of language runtimes:

• Managed: JVM, CLR - with garbage collection and bytecode execution.
• Interpreted: Python, Ruby - that execute code directly or via JIT.
• AOT/Native: Go, Rust, C/C++ - fast startup, low footprint.
• Language-specific toolchains that affect packaging, startup time, and memory footprint.

Runtimes determine application performance characteristics—startup time, latency, throughput, and memory usage. Selecting and tuning the correct runtime is a strategic decision for building high-performing, cost-effective applications.

Advantages of understanding and choosing runtimes:

• Optimized performance and resource utilization for targeted workloads.
• Ability to exploit language features (concurrency, safety, libraries) effectively.
• Trade-offs between developer productivity and operational efficiency.
• Support for cross-platform portability and integration with system tooling.

• Wikipedia Entry
• OpenJDK.org