Java Tutorial: File I/O
Read and write files using java.nio.file.Files, Path, BufferedReader/Writer, and try-with-resources.
Files: persistence beyond the program
Everything in memory disappears when your program ends. Files persist. Java's `java.nio.file` package (NIO.2, Java 7+) is the modern way to work with files — it's simpler, more powerful, and safer than the old `java.io.File`.
What you'll learn in this Java file i/o tutorial
This interactive Java tutorial has 5 hands-on exercises. Estimated time: 18 minutes.
- Writing to a file — `Files.write()` is the simplest way to write a file:
- Reading from a file — Several ways to read:
- BufferedReader for large files — `BufferedReader` reads line by line, efficiently, for large files:
- Path operations — `Path` and `Files` have methods for working with file system structure:
- CSV file processor — Final challenge — no starter code.
Java File I/O concepts covered
- Files: persistence beyond the program