@Override
    public List<HStoreFile> preSelect(List<HStoreFile> filesCompacting) {
      return compactionPolicy.preSelectCompactionForCoprocessor(storeFileManager.getStoreFiles(),
        filesCompacting);
    }
Default StoreEngine creates the default compactor, policy, and store file manager, or their
derivatives.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/DefaultStoreEngine.java