Java File Handling

What is File Handling?

File Handling in Java is the process of creating, reading, writing, updating, and deleting files using Java programs.

👉 It helps programs to store data permanently instead of only in memory.

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📁 What is a File?

A file is a collection of data stored in a storage device (like hard disk).

👉 Examples:

• notes.txt
• data.pdf
• image.jpg

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📂 What is a Directory (Folder)?

A directory (folder) is a container used to store files and other folders.

👉 Example:

Documents/
   ├── notes.txt
   ├── resume.pdf
   └── Images/

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⚙️ What is the File Class?

The File class in Java is used to:

• Create files
• Check file properties
• List files and folders
• Delete files

👉 It belongs to:

java.io package

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🔑 Important Methods (Definition)

• createNewFile() → Creates a new file
• listFiles() → Lists all files in a directory
• isFile() → Checks if it is a file
• isDirectory() → Checks if it is a folder
• getName() → Returns file/folder name
• delete() → Deletes a file

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🔤 String Methods Used in File Handling

👉 File handling often uses String methods:

• toLowerCase() → ignore case
• endsWith() → check file type
• substring() → extract extension
• lastIndexOf() → find extension position

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💾 Why File Handling is Important?

• Store data permanently
• Read/write application data
• Work with system files
• Used in real-world apps (logs, configs, reports)

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Short Conclusion

File handling is a core concept in Java that allows developers to interact with system files and build practical applications.

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