ArgumentCaptor in Mockito

Use it to capture argument values for further assertions.
It should be used during verifications. It is very useful when assert on argument values to complete verification.
It can also be fined through annotation: @Captor
More info here: http://docs.mockito.googlecode.com/hg/org/mockito/ArgumentCaptor.html
and : http://docs.mockito.googlecode.com/hg/org/mockito/Captor.html

Mockito Matchers

When using Mockito you can use MockitoMatchers. You can use predefined ones or create own implementation.
F.e.

assertThat(object, CoreMatchers.equalTo(0));

More examples as well as own implementations here: http://docs.mockito.googlecode.com/hg/org/mockito/Matchers.html

Cannot map request parameters as a Map parameter in Spring MVC

In Spring MVC you cannot map request parameters as a Map parameter in controller method using annotation @RequestParam
It is due to implementation of HandlerMethodInvoker.java, where Spring puts all parameters of the request to the parameter of Map type. Moreover the result map type is MultiValueMap or Linked HashMap.

CachingConnectionFactory for Spring JMS

CachingConnectionFactory is used as the proxy wrapping JMS Connection in the Spring JMS. It prevents from agressively closing and reopening JMS sessions and connections.
It is used for adding caching during usage Spring JMS templates.

<bean id="cachingConnectionFactory" class="org.springframework.jms.connection.CachingConnectionFactory">
  <property name="targetConnectionFactory" ref="connectionFactory"/>
</bean>

Creating directories hierarchical on Linux

Use
mkdir -p directory
to create directory with no error if existing and make parent directories as needed.

@InjectMocks - Mockito

It is an annotation used in Mockito on the variable definition telling Mockito to try to inject by type already defined mocks or spies on the annotated object
f.e.:
@InjectMocks private MyService service = new MyService();

More info here: http://docs.mockito.googlecode.com/hg/org/mockito/InjectMocks.html

Actions throwing exceptions in Spring MVC

When an action in the Spring MVC throws exception, you can handle it with specifying http response code, by annotation on the exception class definition: @ResponseStatus(httpStatus).
When you cannot annotate class, f.e. it is not your exception definition, you can add in the controller a method which is annotated with @ExceptionHandler(yourExceptionClass) and @ResponseStatus(httpStatus)