Add Provide-Capability metadata for OSGi.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1611988 13f79535-47bb-0310-9956-ffa450edef68
Simplify log4j-core bundle activator.

  - The use of LogManager.setFactory() doesn't appear to be all that helpful when the old factory has already been used during class static initialization. A better approach is in the works.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1611990 13f79535-47bb-0310-9956-ffa450edef68
Add LoaderUtil class to isolate ClassLoader utility class.

  - Code based on the Loader class in log4j-core.
  - Provides the functionality from ProviderUtil.findClassLoader() (which will delegate to this class in an upcoming revision).

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1611991 13f79535-47bb-0310-9956-ffa450edef68
Re-use LoaderUtil methods in Loader.

  - Remove duplicated code that was migrated to log4j-api.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1611992 13f79535-47bb-0310-9956-ffa450edef68
Use LoaderUtil in PropertiesUtil.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1611993 13f79535-47bb-0310-9956-ffa450edef68
Add ClassLoader to Provider along with additional methods.

  - Now a Provider can be added outside ProviderUtil which specifies a particular ClassLoader to use.
  - Provides methods for loading the LoggerContextFactory and ThreadContextMap classes specified by a Provider.
  - Added javadocs for Provider methods.
  - Delegated ProviderUtil.findClassLoader() to LoaderUtil.
  - Part of updated OSGi support.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1611998 13f79535-47bb-0310-9956-ffa450edef68
Use the new methods in Provider for loading classes.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1611999 13f79535-47bb-0310-9956-ffa450edef68
Implement BundleActivator for log4j-api.

  - Fixes LOG4J2-373.
  - Added Require-Capability to prevent log4j-api from starting without log4j-core or another bundle with a LoggerContextFactory implementation.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1612002 13f79535-47bb-0310-9956-ffa450edef68
Add more information in changelog about LOG4J2-595.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1612007 13f79535-47bb-0310-9956-ffa450edef68