What is the difference between doGet() and doPost() methods in a Servlet and when is each one used?

The doGet() and doPost() methods are two important methods in a Servlet that handle HTTP GET and POST requests respectively.

The main difference between doGet() and doPost() methods is in how they handle data submission:

• doGet(): This method is used for data retrieval from a server. It appends the form data to the URL and can only handle limited amount of data. doGet() method is safe, idempotent, and cacheable. It is commonly used for fetching data from the server.
• doPost(): This method is used for sending data to the server in a more secure way. It sends data in the message body of the HTTP request, which is not visible in the URL. doPost() method is not safe, not idempotent, and not cacheable. It is commonly used for submitting forms, uploading files, or any sensitive data.

When to use each method:

• Use doGet() when you want to retrieve data from the server and the data does not contain sensitive information.
• Use doPost() when you want to submit data to the server securely, especially for sensitive information like login credentials or payment details.

It is important to use the appropriate method based on the nature of data being exchanged between the client and the server to ensure security and efficiency of the web application.