What is backpressure?

Backpressure is a flow control mechanism between a producer and a consumer that prevents buffer overflow or consumer overload.

In the context of Java, especially in reactive programming (for example, using Project Reactor or RxJava), backpressure allows the consumer to signal to the producer how many elements it is ready to accept. This helps prevent OutOfMemoryError and increases system resilience.

Example: if the data stream is generated faster than the consumer can process, backpressure forces the producer to slow down or pause sending new data until the consumer frees up resources.