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Fixed wrong usage of the HashMap type in a concurrent environment #345

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Merged
merged 1 commit into from
Nov 10, 2025
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Fixed wrong usage of the HashMap type in a concurrent environment #345

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Replace HashMap with ConcurrentHashMap for thread-safe caching in Fin… 
…dRepositoriesByUserIdCache and findRepositories method
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@rcardin
rcardin committed Sep 11, 2025
commit 0c138f3f3dec240e8c4acb2c33fa18472b85c280
4 changes: 2 additions & 2 deletions src/data/articles/structured-concurrency-jdk-25/index.mdx
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Expand Up @@ -384,7 +384,7 @@ We can copy from the previous article the implementation of the `FindRepositorie
```java
class FindRepositoriesByUserIdCache implements FindRepositoriesByUserIdPort {

private final Map<UserId, List<Repository>> cache = new HashMap<>();
private final Map<UserId, List<Repository>> cache = new ConcurrentHashMap<>();

public FindRepositoriesByUserIdCache() {
cache.put(
Expand Down Expand Up @@ -504,7 +504,7 @@ class GitHubRepository
@Override
public Map<UserId, List<Repository>> findRepositories(List<UserId> userIds)
throws InterruptedException {
var repositoriesByUserId = new HashMap<UserId, List<Repository>>();
var repositoriesByUserId = new ConcurrentHashMap<UserId, List<Repository>>();
try (var scope = StructuredTaskScope.open(Joiner.awaitAll())) {
userIds.forEach(
userId -> {
Expand Down