How to compile the libsqlitejdbc.so?
Recently I used SQLite in Java, so I download the sqlite-jdbc.
In this project, there is the following paragraph：
Since sqlite-jdbc-3.6.19, the natively compiled SQLite engines will be used for the following operating systems:
Windows XP, Vista (Windows, x86 architecture, x86_64)
Mac OS X 10.4 (Tiger), 10.5(Leopard), 10.6 SnowLeopard (for i386, x86_64, Intel CPU machines)
Linux i386 (Intel), amd64 (64-bit X86 Intel processor)
This means that the native SQLite they are using is compiled from the official version, something like:
I want to know how did they compile the source code so that I can modify some SQLite source code and apply it to sqlite-jdbc according to my need.
The sqlite-jdbc project page, which your link reaches, lists among its top-level files a "README_BUILD.md", whose link reaches How to compile a new version of SQLiteJDBC. That is where the answer to your question lies. This forum is about the SQLite library itself, its CLI shell, and how it works -- not about how it might be built into the multitude of applications, adapters, languages, and libraries that happen to use SQLite.
The nitty-gritty of "how did they compile the source code" is in a file listed on the project page named "Makefile". You can follow the build instructions with a -n flag added to the make invocation to get make to say what it would do instead of doing it.