Completable Future

In Java CompletableFutures, the methods apply(), accept(), and run() are used to handle the results of a computation or task when it completes. Here's the difference between these methods:

1. apply(): This method is used when you want to apply a function to the result of a computation and return a new CompletableFuture with the transformed result. It takes a Function as a parameter that specifies how to transform the result. The apply() method returns a CompletableFuture that will eventually hold the transformed result.

Example usage:

CompletableFuture<Integer> future = CompletableFuture.supplyAsync(() -> 5);
CompletableFuture<String> transformedFuture = future.thenApply(result -> result * 2)
                                                  .thenApply(result -> "Transformed: " + result);

2. accept(): This method is used when you want to perform an action with the result of a computation, but you don't need to return anything. It takes a Consumer as a parameter that specifies the action to be performed on the result. The accept() method returns a CompletableFuture that completes when the action is done.

Example usage:

CompletableFuture<Integer> future = CompletableFuture.supplyAsync(() -> 5);
CompletableFuture<Void> actionFuture = future.thenAccept(result -> System.out.println("Result: " + result));

3. run(): This method is used when you want to perform an action after the completion of a computation, without using the result of the computation. It takes a Runnable as a parameter that specifies the action to be performed. The run() method returns a CompletableFuture that completes when the action is done.

Example usage:

CompletableFuture<Void> future = CompletableFuture.supplyAsync(() -> 5)
                                                 .thenRun(() -> System.out.println("Computation completed"));

In summary, apply() is used when you want to transform the result and return a new CompletableFuture, accept() is used when you want to perform an action with the result, and run() is used when you want to perform an action without using the result.