code: private ClassLoader resolve(Set<? extends File> classPath) {
          ClassLoader classLoader = classLoaders.get(classPath);
          if (classLoader == null) {
              classLoader = doResolve(classPath);
              classLoaders.put(classPath, classLoader);
          }
          return classLoader;
      }
docs: Resolves a class path to a class loader. If a class loader for the same file collection was created
  previously, the previous class loader is returned.
  
  @param classPath The class path to consider.
  @return A class loader for the supplied class path.