Before this commit, creating a CompositeMap from two maps with the same
key has strange results, such as entrySet returning duplicate entries
with the same key.
After this commit, we give precedence to the first map by filtering out
all entries in the second map that are also mapped by the first map.
See gh-32245
Prior to this commit, MethodIntrospector failed to properly detect
bridge methods for subsequent invocations of selectMethods() with the
same targetType and MetadataLookup, if such subsequent invocations
occurred after the ApplicationContext had been refreshed.
The reason this occurs is due to the following.
- Class#getDeclaredMethods() always returns "child copies" of the
underlying Method instances -- which means that `equals()` should be
used instead of `==` whenever the compared Method instances can come
from different sources (such as the static caches mentioned below).
- BridgeMethodResolver caches resolved bridge methods in a static cache
-- which is never cleared.
- ReflectionUtils caches declared methods in a static cache
-- which gets cleared when an ApplicationContext is refreshed.
Consequently, if you attempt to load an ApplicationContext twice in the
same ClassLoader, the second attempt uses the existing, populated cache
for bridged methods but a cleared, empty cache for declared methods.
This results in new invocations of Class#getDeclaredMethods(), and
identity checks with `==` then fail to detect equivalent bridge methods.
This commit addresses this by additionally comparing bridge methods
using `equals()` in MethodIntrospector.selectMethods().
Note that the `==` checks remain in place as an optimization for when
`equals()` is unnecessary.
Closes gh-32586
This commit replaces `@Nonnull(when = When.MAYBE)` meta-annotation in
`org.springframework.lang.Nullable` by `@CheckForNull` in order to
prevent `unknown enum constant When.MAYBE` compilation warnings.
Closes gh-27183
Javadoc doesn't seem to like having `e.g.` as it thinks the sentence
ends there, which is usually incorrect and results in broken descriptions.
This commit rewords the doc strings slightly to avoid problematic parts.
Closes gh-32532
This commit introduces null-safety checks for spring-core at build-time
in order to validate the consistency of Spring null-safety annotations
and generate errors when inconsistencies are detected during a build
(similar to what is done with Checkstyle).
In order to make that possible, this commit also introduces a new
org.springframework.lang.Contract annotation inspired from
org.jetbrains.annotations.Contract, which allows to specify semantics
of methods like Assert#notNull in order to prevent artificial
additional null checks in Spring Framework code base.
This commit only checks org.springframework.core package, follow-up
commits will also extend the analysis to other modules, after related
null-safety refinements.
See gh-32475
Historically, we have rarely intentionally thrown a
NullPointerException in the Spring Framework. Instead, we prefer to
throw either an IllegalArgumentException or IllegalStateException
instead of a NullPointerException.
However, changes to the code in recent times have introduced the use of
Objects.requireNonNull(Object) which throws a NullPointerException
without an explicit error message.
The latter ends up providing less context than a NullPointerException
thrown by the JVM (since Java 14) due to actually de-referencing a
null-pointer. See https://openjdk.org/jeps/358.
In light of that, this commit revises our current use of
Objects.requireNonNull(Object) by removing it or replacing it with
Assert.notNull().
However, we still use Objects.requireNonNull(T, String) in a few places
where we are required to throw a NullPointerException in order to
comply with a third-party contract such as Reactive Streams.
Closes gh-32430
Rework AnnotatedElementAdapter to avoid cloning the underlying
Annotation array if it is empty when getAnnotations() is called.
Additionally, make the class static and add a factory method that
returns a singleton instance for null or empty Annotation arrays.
Closes gh-32405
Sam Brannen
Arjen Poutsma
Juergen Hoeller
laterlaugh
Sébastien Deleuze
Mikaël Francoeur
Łukasz Jernaś
T45K
Stéphane Nicoll
Johnny Lim
Yanming Zhou
Patrick Strawderman