There are several best practices that you can follow to improve the security of a Java application:
Use secure coding practices: Follow best practices for secure coding, such as using input validation, sanitizing user input, and avoiding common vulnerabilities such as SQL injection, cross-site scripting (XSS), and cross-site request forgery (CSRF).
Use a secure connection: Use Secure Sockets Layer (SSL) or Transport Layer Security (TLS) to encrypt communication between the application and the server, and between the application and the client.
Use secure authentication and authorization: Use strong passwords and two-factor authentication to secure access to the application, and implement proper authorization controls to ensure that users can only access the resources and functionality that they are allowed to access.
Use secure storage: Store sensitive data such as passwords and confidential documents in encrypted form, and use secure storage mechanisms such as keystores and password managers to protect the data.
Use security testing: Regularly test the application for vulnerabilities using tools such as static code analysis and dynamic testing.
Use security patches and updates: Keep the application and its dependencies up to date with the latest security patches and updates to fix known vulnerabilities.
Use security monitoring: Monitor the application for security breaches and anomalies, and take appropriate actions to prevent or mitigate potential attacks.
By following these best practices, you can help to ensure the security of your Java application and protect it against potential threats.