Difference between Classpath:* & Classpath*: in Spring

The difference between these two is the way the resources are found when a regular expression is given for match.

classpath*: -> This special prefix specifies that all classpath resources that match the given name must be obtained
(internally, this essentially happens via a ClassLoader.getResources(...) call), and then merged to form the final application context definition.

Ex classpath*:app*.xml && classpath:app*.xml is

With spring xmls, app1.xml and app2.xml and beans in app2.xml referring to app1.xml

- classpath:app*.xml will give errors if app1.xml and app2.xml are in two different classpath folders(It tries to find a matching app1 or app2 in classpath , and when
found doesnt continue to search further with other classpath locations.)

- classpath*:app*.xml will never give errors(searches for all classpath folders)

classpath* will search all classpath folder whereas classpath: will concentrate on one resource.

This also works for location attribute of PropertyPlaceHolderConfig

<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations" value="classpath*:jdbc.properties"></property>
</bean>

But important thing to be noted here is that property name is locations and not location.


One more difference with classpath*:config.xml and classpath:*config.xml

is that

classpath:*config.xml - if file(matching *config) isnt present it shows error in console

classpath*:*config.xml just ignores teh error if no file is present in the classpath.

classpath*: basically refers to a list of resources and a list can be empty.
classpath: simply points to a certain resource and if this is empty (where one would have expected it to exist) it would generate an error.


Note:

Note that "classpath*:" when combined with Ant-style patterns will only work reliably with at
least one root directory(IMPORTANT) before the pattern starts, unless the actual target files
reside in the file system.This means that a pattern like "classpath*:*.xml" will not retrieve
files from the root of jar files but classpath*:META-INF/* will search as expected.