The software described in this documentation is either in Extended Support or Sustaining Support. See https://www.oracle.com/us/support/library/enterprise-linux-support-policies-069172.pdf for more information.
Oracle recommends that you upgrade the software described by this documentation as soon as possible.

2.3.1 Limiting the Scope

Understanding the composition of the code used by an application is a critical part of the planning process. Since many legacy applications are large (millions of lines of code), simply trying to understand the layout of the source tree and the types of files can become a complex task. Developers seldom remove old, unused code from the source code directory, and seldom are there different build instructions for each targeted deployment scenario.

As an application evolves, new functionality gets added, some business functionality becomes redundant or irrelevant, and some modules are no longer required for a given deployment scenario. Hence, for a large application, understanding which files within the source distribution are actually getting used to build the application for the given deployment scenario can help limit the scope of the porting activity.