Add BridgeMethodResolver#isJava6VisibilityBridgeMethodPair to
distinguish between (a) bridge methods introduced in Java 6 to
compensate for inheriting public methods from non-public superclasses
and (b) bridge methods that have existed since Java 5 to accommodate
return type covariance and generic parameters.
In the former case, annotations should be looked up from the original
bridged method (SPR-7900). In the latter, the annotation should be
looked up against the bridge method itself (SPR-8660).
As noted in the Javadoc for the new method, see
http://stas-blogspot.blogspot.com/2010/03/java-bridge-methods-explained.html
for a useful description of the various types of bridge methods, as
well as http://bugs.sun.com/view_bug.do?bug_id=6342411, the bug fixed in
Java 6 resulting in the introduction of 'visibility bridge methods'.
Issue: SPR-8660, SPR-7900
Previously, #containsBean Javadoc advertised that a true return value
indicates that a call to #getBean for the same name would succeed.
This is actually not the case, and has never been. The semantics
of #containsBean have always been to indicate whether a bean definition
with the given name is definied or a singleton instance with the given
name has been registered.
The Javadoc now reflects this accurately.
Issue: SPR-8690
Commit http://bit.ly/nXumTs ensured that component methods and fields
marked with 'common annotations' such as @Resource, @PostConstruct and
@PreDestroy are invoked/assigned once and only once, even if multiple
instances of the CommonAnnotationBeanPostProcessor are processing the
same bean factory.
The implementation works against the InjectionMetadata API, adding and
removing these members from sets that track whether they are already
'externally managed', i.e. that another CABPP has already handled them,
thus avoiding redundant processing.
Prior to this change, the #remove operations against these sets were
not synchronized. In a single-threaded context this is fine thanks to
logic in AbstractAutowireCapableBeanFactory#doCreateBean that checks to
see whether a given bean definition has already been post processed.
However, as reported by SPR-8598, certain cases involving multiple
threads and annotated prototype-scoped beans can cause concurrent
modification exceptions during the #remove operation (ostensibly because
another thread is attempting to do the same removal at the same time,
though this has yet to be reproduced in isolation).
Now the sets originally introduced by the commit above are decorated
with Collections#synchronizedSet and any iterations over those sets
are synchronized properly. This change should have low performance
impact as such processing happens at container startup time (save for
non-singleton lookups at runtime), and there should be little
contention in any case.
Issue: SPR-8598
Prior to this change, a parsing exception would be thrown if a
<description> element was placed within a <map><entry/></map>
element. The beans XSD has always permitted this arrangement,
but BeanDefinitionParserDelegate did not respect it. The latter now
simply ignores any <description> element, rather than failing.
Issue: SPR-8563
For the particular use case detailed in SPR-8514, with this change we
now attempt to determine the object type of a FactoryBean through its
generic type parameter if possible.
For (a contrived) example:
@Configuration
public MyConfig {
@Bean
public FactoryBean<String> fb() {
return new StringFactoryBean("foo");
}
}
The implementation will now look at the <String> generic parameter
instead of attempting to instantiate the FactoryBean in order to call
its #getObjectType() method.
This is important in order to avoid the autowiring lifecycle issues
detailed in SPR-8514. For example, prior to this change, the following
code would fail:
@Configuration
public MyConfig {
@Autowired Foo foo;
@Bean
public FactoryBean<String> fb() {
Assert.notNull(foo);
return new StringFactoryBean("foo");
}
}
The reason for this failure is that in order to perform autowiring,
the container must first determine the object type of all configured
FactoryBeans. Clearly a chicken-and-egg issue, now fixed by this
change.
And lest this be thought of as an obscure bug, keep in mind the use case
of our own JPA support: in order to configure and return a
LocalContainerEntityManagerFactoryBean from a @Bean method, one will
need access to a DataSource, etc -- resources that are likely to
be @Autowired across @Configuration classes for modularity purposes.
Note that while the examples above feature methods with return
types dealing directly with the FactoryBean interface, of course
the implementation deals with subclasses/subinterfaces of FactoryBean
equally as well. See ConfigurationWithFactoryBeanAndAutowiringTests
for complete examples.
There is at least a slight risk here, in that the signature of a
FactoryBean-returing @Bean method may advertise a generic type for the
FactoryBean less specific than the actual object returned (or than
advertised by #getObjectType for that matter). This could mean that an
autowiring target may be missed, that we end up with a kind of
autowiring 'false negative' where FactoryBeans are concerned. This is
probably a less common scenario than the need to work with an autowired
field within a FactoryBean-returning @Bean method, and also has a clear
workaround of making the generic return type more specific.
Issue: SPR-8514
Prior to this change, (Context)SingletonBeanFactoryLocator used
BeanFactoryUtils#beanOfType(ListableBeanFactory, Class) to locate the
bean of type BeanFactory.
The more modern approach is to use BeanFactory#getBean(Class), which
removes a dependency on ListableBeanFactory interface while at the same
time opening the implementation up to respecting autowiring exclusions,
primary metadata, etc.
Issue: SPR-8489
Prior to this change, @Autowired injection against an instance of a
subclass having different visibility than its superclass would fail
if the @Autowired method is declared only in the superclass. This is due
to an apparent change in the rules around bridge method generation
between Java 5 and Java 6, and possibly even varying across compiler
vendors.
Now, BridgeMethodResolver is used consistently when detecting
@Autowired, @Inject and @Resource metadata to bypass these bridge
methods if they exist.
Issue: SPR-7900
Prior to this change, AbstractAutowireCapableBeanFactory did not support
a default ParameterNameDiscoverer. This meant that attempting to use
<constructor-arg name=".."> syntax would fail (with a fairly obscure
exception) as that feature depends on a ParameterNameDiscoverer to
introspect the constructor arguments.
This lack of a default was originally intended to avoid a dependency on
ASM, but now that (a) .asm is a built-in module and (b) .beans has a
non-optional compile-time dependency on .asm, there is no reason not to
provide this default.
The net effect is that in a number of locations throughout the
framework, namely in GenericApplicationContext and
AbstractRefreshableApplicationContext, it is no longer necessary to
explicitly call AACBF#setParameterNameDiscoverer. This also means that
using a naked BeanFactory (likely for testing scenarios) is that much
easier.
Issue: SPR-8184
Prior to this change, DirectFieldAccessor would ignore fields shadowed
in subclasses, favoring the last field processed, which happens to be
the most super declaration based on the way ReflectionUtils.doWithFields
works.
Because the locally shadowed field may be of a different type that the
superclass declaration, it is most correct to preserve and work with
the shadowed field.
Issue: SPR-8398
Attempt to access and modify the system environment works on OS X /
Linux but not under Windows. Does not represent any real failure for
production code - the need to modify the system environment is a
testing concern only, and one we can probably live without, considering
the losing battle necessary to make such a hack cross-platform.
Issue: SPR-8245
AbstractEnvironment and subclasses now register a reserved default
profile named literally 'default' such that with no action on the part
of the user, beans defined against the 'default' profile will be
registered - if no other profiles are explicitly activated.
For example, given the following three files a.xml, b.xml and c.xml:
a.xml
-----
<beans> <!-- no 'profile' attribute -->
<bean id="a" class="com.acme.A"/>
</beans>
b.xml
-----
<beans profile="default">
<bean id="b" class="com.acme.B"/>
</beans>
c.xml
-----
<beans profile="custom">
<bean id="c" class="com.acme.C"/>
</beans>
bootstrapping all of the files in a Spring ApplicationContext as
follows will result in beans 'a' and 'b', but not 'c' being registered:
ApplicationContext ctx = new GenericXmlApplicationContext();
ctx.load("a.xml");
ctx.load("b.xml");
ctx.load("c.xml");
ctx.refresh();
ctx.containsBean("a"); // true
ctx.containsBean("b"); // true
ctx.containsBean("c"); // false
whereas activating the 'custom' profile will result in beans 'a' and
'c', but not 'b' being registered:
ApplicationContext ctx = new GenericXmlApplicationContext();
ctx.load("a.xml");
ctx.load("b.xml");
ctx.load("c.xml");
ctx.getEnvironment().setActiveProfiles("custom");
ctx.refresh();
ctx.containsBean("a"); // true
ctx.containsBean("b"); // false
ctx.containsBean("c"); // true
that is, once the 'custom' profile is activated, beans defined against
the the reserved default profile are no longer registered. Beans not
defined against any profile ('a') are always registered regardless of
which profiles are active, and of course beans registered
against specific active profiles ('c') are registered.
The reserved default profile is, in practice, just another 'default
profile', as might be added through calling env.setDefaultProfiles() or
via the 'spring.profiles.default' property. The only difference is that
the reserved default is added automatically by AbstractEnvironment
implementations. As such, any call to setDefaultProfiles() or value set
for the 'spring.profiles.default' will override the reserved default
profile. If a user wishes to add their own default profile while
keeping the reserved default profile as well, it will need to be
explicitly redeclared, e.g.:
env.addDefaultProfiles("my-default-profile", "default")
The reserved default profile(s) are determined by the value returned
from AbstractEnvironment#getReservedDefaultProfiles(). This protected
method may be overridden by subclasses in order to customize the
set of reserved default profiles.
Issue: SPR-8203
@Autowired, @Value and other annotations cannot be applied within
Spring Bean(Factory)PostProcessor types, because they themselves
are processed using BeanPostProcessors. Javadoc and reference docs
have been updated to reflect.
Issue: SPR-4935, SPR-8213
Chris Beams
Sam Brannen
Juergen Hoeller
Keith Donald