JUST-IN-TIME COMPILATION Further blurring the distinction between interpreters, byte-code interpreters and compilation is just-in-time compilation (or JIT), a technique in which the intermediate representation is compiled to native machine code at runtime. This confers the efficiency of running native code, at the cost of startup time and increased memory use when the byte code or AST is first compiled. Adaptive optimization is a complementary technique in which the interpreter profiles the running program and compiles its most frequently-executed parts into native code. Both techniques area few decades old, appearing in languages such as Smalltalk in the s. Just-in-time compilation has gained mainstream attention amongst language implementors in recent years, with Java, Python and the NET Framework all now including JITs.
