Sync Over Async (ARCH4023)

Key java.async.blocking-future-get · Severity error · Category async

Blocking on an asynchronous operation with get()/join() from a synchronous context risks deadlock and thread-pool starvation, and defeats the purpose of going async in the first place.

Incorrect

public Report build() {
    CompletableFuture<Data> f = fetchAsync();
    Data data = f.get();          // synchronous block
    return render(data);
}

Correct

public CompletableFuture<Report> build() {
    return fetchAsync()
        .thenApply(this::render); // chain, don't block
}

Fix

Replace the blocking get()/join() with thenApply/thenCompose to chain asynchronously and return the future.