Just In Time Compiler
A Just In Time (JIT) compiler is a runtime compilation technique that translates bytecode or intermediate code into native machine code during program execution, rather than ahead of time. It dynamically optimizes code based on actual usage patterns, enabling performance improvements by compiling frequently executed 'hot' paths. This approach bridges the gap between interpreted languages and statically compiled ones, offering both flexibility and speed.
Developers should learn about JIT compilers when working with high-performance applications in languages like Java, JavaScript, or .NET, as they are critical for achieving near-native execution speeds. It is essential for optimizing runtime performance in virtual machines, such as the Java Virtual Machine (JVM) or V8 engine, where it reduces startup times and adapts to dynamic workloads. Understanding JIT compilation helps in debugging performance issues and writing code that leverages its optimizations, such as avoiding deoptimizations in hot loops.