Sam Brannen ca62119cb3 Evict context from ContextCache before loading a new context ...

Since Spring Framework 4.2, DefaultContextCache supported an LRU (least
recently used) eviction policy via a custom LruCache which extended
LinkedHashMap. The LruCache reacted to LinkedHashMap's
removeEldestEntry() callback to remove the LRU context if the maxSize
of the cache was exceeded.

Due to the nature of the implementation in LinkedHashMap, the
removeEldestEntry() callback is invoked after a new entry has been
stored to the map.

Consequently, a Spring ApplicationContext (C1) was evicted from the
cache after a new context (C2) was loaded and added to the cache,
leading to failure scenarios such as the following.

- C1 and C2 share an external resource -- for example, a database.
- C2 initializes the external resource with test data when C2 is loaded.
- C1 cleans up the external resource when C1 is closed.
- C1 is loaded and added to the cache.
- C2 is loaded and added to the cache before C1 is evicted.
- C1 is evicted and closed.
- C2 tests fail, because C1 removed test data required for C2.

To address such scenarios, this commit replaces the custom LruCache
with custom LRU eviction logic in DefaultContextCache and revises
the put(MergedContextConfiguration, ApplicationContext) method to
delegate to a new evictLruContextIfNecessary() method.

This commit also introduces a new put(MergedContextConfiguration,
LoadFunction) method in the ContextCache API which is overridden by
DefaultContextCache to ensure that an evicted context is removed and
closed before a new context is loaded to take its place in the cache.

In addition, DefaultCacheAwareContextLoaderDelegate has been revised to
make use of the new put(MergedContextConfiguration, LoadFunction) API.

Closes gh-21007

2025-09-04 14:13:10 +02:00

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main

Evict context from ContextCache before loading a new context

2025-09-04 14:13:10 +02:00

test

Evict context from ContextCache before loading a new context

2025-09-04 14:13:10 +02:00