To deal with the source code of the bytecode compilations associated with the Java classes it is advisable to use a program such as JD-GUI, otherwise it can be quite complicated, especially if your computing level is not very high.
It acts as a decompiler by extracting the code through the so-called JAR packages, allowing you to export it in ZIP, TXT and LOG formats. Its operation is based on the action of dragging and dropping the corresponding files, making it extremely simple.
After loading the source code in question, JD-GUI shows it in comfortable tabs that have options such as highlighting syntax and numbering lines. Through the integrated search engine you can instantly find any term.