Full-Stack Developer Interview Questions and Answers
Ques 51. Explain the concept of optimistic and pessimistic concurrency control in database transactions.
Optimistic concurrency control assumes no conflict and allows transactions to proceed, checking for conflicts only at the end. Pessimistic concurrency control locks data to prevent conflicts until the transaction is complete.
Ques 52. What is the purpose of the 'this.props.children' in React.js?
'this.props.children' in React.js allows components to pass children elements to other components, enabling the composition of complex UI structures.
Ques 53. Explain the concept of A/B testing and its use in optimizing user experiences.
A/B testing involves comparing two versions of a web page to determine which performs better. It helps optimize user experiences by analyzing user behavior and preferences.
Ques 54. What is the purpose of the 'aria-' attributes in HTML and when are they used?
The 'aria-' attributes in HTML are used for accessibility, providing additional information to assistive technologies. They help convey roles, states, and properties to users with disabilities.
Ques 55. Explain the concept of JWT expiration and refresh tokens in authentication.
JWT expiration ensures tokens have a limited validity period. Refresh tokens are used to obtain a new JWT without requiring the user to re-enter their credentials, enhancing security.
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