Mono.fromCallable vs. Mono.justOrEmpty in Spring Reactive

Date: 2025-01-15

Spring Reactive's Mono handles single-value asynchronous streams. Mono.fromCallable creates a Mono from a Callable, lazily executing it upon subscription, ideal for potentially blocking operations like database queries. Conversely, Mono.justOrEmpty creates a Mono from a value; it emits the value if non-null, otherwise completes empty, gracefully handling optional values. Choose fromCallable for deferred, asynchronous execution and justOrEmpty for managing potentially null data within reactive streams.

Read more: https://www.javacodegeeks.com/spring-reactive-mono-fromcallable-vs-mono-justorempty.html