@Override
    public List<String> getKeys() throws IOException {
      checkKeyProvider();
      return keyProvider.getKeys();
    }
Compares two encryption key strengths.

@param path1 First  path to compare
@param path2 Second path to compare
@param encryptionShim2 The encryption-shim corresponding to path2.
@return 1 if path1 is stronger; 0 if paths are equals; -1 if path1 is weaker.
@throws IOException If an error occurred attempting to get key metadata
shims/0.23/src/main/java/org/apache/hadoop/hive/shims/Hadoop23Shims.java