Java.Streams.What file access modes does RandomAccessFile have?

📜 File Access Modes in RandomAccessFile

1. "r" — Read-only

• Read operations only.
• No writing allowed.
• File must exist, or you’ll get FileNotFoundException.

🔹 Use Case: Inspect a file without modifying it.

RandomAccessFile raf = new RandomAccessFile("input.txt", "r");

2. "rw" — Read and Write

• Allows both reading and writing.
• File will be created if it doesn’t exist.
• Writes may be buffered (not immediately flushed to disk).

🔹 Use Case: Modify or append data to files.

RandomAccessFile raf = new RandomAccessFile("data.bin", "rw");

. "rws" — Read, Write, Sync metadata & content

• Like "rw" but synchronously updates:
  • File content
  • File metadata (like timestamps)
• More durable (good for logs), but slower due to forced disk sync.

🔹 Use Case: Critical logs or journaling systems.

RandomAccessFile raf = new RandomAccessFile("log.txt", "rws");

4. "rwd" — Read, Write, Sync content only

• Like "rw" but only synchronously writes file content (not metadata).
• Slightly faster than "rws" while still safe for data integrity.

🔹 Use Case: When you care about the data being saved, not file attributes.

RandomAccessFile raf = new RandomAccessFile("important.txt", "rwd");

🧵 TL;DR Table

Mode	Read	Write	Auto-create file	Sync content?	Sync metadata?	Use Case
"r"	✅	❌	❌	❌	❌	Read-only access
"rw"	✅	✅	✅	❌	❌	General read/write
"rws"	✅	✅	✅	✅	✅	Durable writes + metadata
"rwd"	✅	✅	✅	✅	❌	Safe writes (faster than rws)