Bootstrapping (compilers)

Bootstrapping is a computer science method to create a programming language, that is compiled with itself. In most cases, a compiler is written in a language, where the compiler is rewritten for the language that is being compiled. 
Most popular programming languages all follow a pattern of bootstrapped compilers. Some include Java, C#, C, Rust, Ruby, Python, and more.
Process.
Bootstrapping usually has just a few stages: 
Early Bootstrapping.
In 1962, Tim Hart, and Mike Levin wrote a compiler for LISP, inside of LISP. They improved the compiler until it was capable of compiling itself.