How were the compilers written in Java originally compiled?

Question

Programming

I read that the C compiler is written in the language itself. Question: how did the developers compile the compiler written in a high-level language then? After all, the processor understands its machine instructions.

Answer 1

See "Spreading the Compiler". Briefly - a compiler is created (in mashcode, assembler, or another language) for the minimum subset of the language suitable for development. Then, on this subset, a compiler is written that can compile this subset itself. Well, then the process continues iteratively, features are added to the language, a compiler is added, and so on.

Answer 2

I will add. Here is a good description of how it all happens.
Everything is done in 3 phases.
https://gcc.gnu.org/install/build.html

Answer 3

So finish reading the history of the creation of the C language, there are a lot of quite interesting articles about this, including in Russian.
At first there were only instructions that were entered directly, then through punched cards / punched tapes, then they wrote the assembly language, then they wrote the language b, in which they wrote C, then they recompiled C in C and so on.