ProviderManager初始化动作不再在构造方法中实现 (#50)

* 新增com.ctrip.framework.foundation.spi.ProviderManager.initialize方法，在使用自定义的ProviderManager实现时，不再因自动初始化com.ctrip.framework.foundation.internals.DefaultProviderManager和com.ctrip.framework.foundation.internals.NullProviderManager，而打印干扰日志

* 新增com.ctrip.framework.foundation.spi.ProviderManager.initialize方法，在使用自定义的ProviderManager实现时，不再因自动初始化com.ctrip.framework.foundation.internals.DefaultProviderManager和com.ctrip.framework.foundation.internals.NullProviderManager，而打印干扰日志

* update CHANGES.md

* update CHANGES.md,使其更加简短明了

* Update apollo-core/src/main/java/com/ctrip/framework/foundation/spi/ProviderManager.java

Co-authored-by: Jason Song <[email protected]>

* update CHANGES.md

* update CHANGES.md

---------

Co-authored-by: Jason Song <[email protected]>

Author: s281542686

CHANGES.md

@@ -5,7 +5,7 @@ Release Notes.
 Apollo Java 2.3.0
 
 ------------------
-* 
+* [add an initialize method to avoid DefaultProviderManager's logic being triggered when using custom ProviderManager.](https://github.com/apolloconfig/apollo-java/pull/50)
 
 ------------------
 All issues and pull requests are [here](https://github.com/apolloconfig/apollo-java/milestone/3?closed=1)

apollo-core/src/main/java/com/ctrip/framework/foundation/Foundation.java

@@ -44,6 +44,7 @@ private static ProviderManager getManager() {
         synchronized (LOCK) {
           if (s_manager == null) {
             s_manager = ServiceBootstrap.loadPrimary(ProviderManager.class);
+            s_manager.initialize();
           }
         }
       }

apollo-core/src/main/java/com/ctrip/framework/foundation/internals/DefaultProviderManager.java

@@ -31,7 +31,8 @@ public class DefaultProviderManager implements ProviderManager {
   private static final Logger logger = LoggerFactory.getLogger(DefaultProviderManager.class);
   private Map<Class<? extends Provider>, Provider> m_providers = new LinkedHashMap<>();
 
-  public DefaultProviderManager() {
+  @Override
+  public void initialize() {
     // Load per-application configuration, like app id, from classpath://META-INF/app.properties
     Provider applicationProvider = new DefaultApplicationProvider();
     applicationProvider.initialize();

apollo-core/src/main/java/com/ctrip/framework/foundation/spi/ProviderManager.java

@@ -25,6 +25,11 @@ public interface ProviderManager extends Ordered {
 
   <T extends Provider> T provider(Class<T> clazz);
 
+  /**
+   * @since 2.3.0
+   */
+  default void initialize() {}
+
   @Override
   default int getOrder() {
     return Ordered.LOWEST_PRECEDENCE;