A Just-In-Time (JIT) compiler is a type of compiler that dynamically compiles code at runtime, as opposed to traditional ahead-of-time (AOT) compilers which compile code before execution.

This allows the JIT compiler to optimize code specifically for the current execution environment, resulting in improved performance and reduced memory usage. The JIT compiler works by analyzing the code as it is executed, identifying hotspots or frequently used code paths, and compiling these portions into native machine code for faster execution.

This process helps to eliminate the overhead of interpreting and translating code on the fly, leading to significant performance improvements for applications. One of the key advantages of JIT compilation is its ability to adapt to changes in the execution environment.

This means that the compiler can make optimizations based on the specific hardware and software configurations of the system, resulting in code that is highly optimized for the current environment. JIT compilers are commonly used in modern programming languages and virtual machines, such as Java and .NET, to improve the performance of applications running on these platforms.

By dynamically compiling code at runtime, JIT compilers help to strike a balance between performance and flexibility, making them a valuable tool for software developers looking to optimize their applications. In summary, a JIT compiler is a dynamic compiler that optimizes code at runtime, improving performance and reducing memory usage by compiling code specifically for the current execution environment.

Its ability to adapt to changes in the system makes it a valuable tool for developers looking to optimize their applications for maximum efficiency.