* finish unit test for AbstractMethodConfig
* finish unit test for AbstractReferenceConfig
* move to right package
* finish unit test for AbstractReferenceConfig
* finish unit test for AbstractMethodConfig
* finish unit test for AbstractReferenceConfig
* move to right package
* finish unit test for AbstractReferenceConfig
* unit test for AbstractServiceConfig, also fix logic issue in setListener/getListener
* use three different kinds of cache factory to increase test coverages
* add unit test cases for dubbo-filter module
* add copyright and made small refactor
* make sure Jcache will exceed expired period
1. Use org.junit.Assert instead of junit.framework.Assert(@Deprecated since Junit 4)
2. Use assertTrue and other assert methods through static import to make codes easier to read
* Extension: Enhanced Thread Pool
A thread pool that can provide faster processing speeds when there are more tasks (of course it consumes more resources)
* When the number of tasks exceeds the core size, a new thread is first started to execute the task instead of putting it into the queue.
* When the number of tasks is lower than the core size for a long time, the core size threads are maintained and redundant threads are recycled.
* Compared to the fixed pool：When there are more tasks, provide more workers to handle the tasks.
* Compared to the cached pool：The task queue in the cached pool is actually a SynchronousQueue and does not have the ability to cache tasks.
* Whether to fail fail or put into a queue when a thread runs out：Both are feasible and need to consider which way should be applied according to the business scenario. Delayed scenarios are not allowed. Failfast is more reasonable than queues. However, if there is a certain tolerance for delays, queues are more reasonable than failfast.
* remove * in import
* add license to fix ci failure
* rename the thread pool to EagerThreadPool
modify sth with the code review
format the code file
* remove '*' in import statement
* throw NullPointerException if the param is null.
* throw NullPointerException if the param is null.
* catch throwable and decrease submitted task count anyway
* Manually merge pull request #1486, to make travis ci and codecov work after apache incubator transition.
* update pom license, scm, maillists, issuemanagement, add DISCLAIMER (#1491)
Huxing Zhang