code: private void enhance(List<File> files) throws MojoExecutionException {
          Options opts = getOptions();
  
          // list of input files
          String[] args = getFilePaths(files);
  
          boolean ok;
  
          final ClassLoader original = Thread.currentThread().getContextClassLoader();
          try {
              if (!tmpClassLoader) {
                  extendRealmClasspath();
              }
  
              ok = PCEnhancer.run(args, opts);
          } finally {
              // We may have change the TCCL, restore the original one
              Thread.currentThread().setContextClassLoader(original);
          }
  
          if (!ok) {
              throw new MojoExecutionException("The OpenJPA Enhancer tool detected an error, check log");
          }
      }
docs: Processes a list of class file resources that are to be enhanced.
  
  @param files class file resources to enhance.
  @throws MojoExecutionException if the enhancer encountered a failure