actually it looks like this is not sufficient:
https://github.com/aaghevli/parquet-mr/blob/ab4cb69e09b109f82e92de8ed21925d75751eef0/parquet-
```
pig/src/main/java/parquet/pig/ParquetLoader.java#L146
parquetInputFormat = new UnregisteringParquetInputFormat(location);
inputFormatCache.put(location, parquetInputFormat);
```
I think you'd want to wrap the key in a new String to avoid that the value refers to the key:
```
inputFormatCache.put(new String(location), parquetInputFormat);
```
http://docs.oracle.com/javase/7/docs/api/java/util/WeakHashMap.html
"Implementation note: The value objects in a WeakHashMap are held by ordinary strong references. Thus care should be taken to ensure that value objects do not strongly refer to their own keys, either directly or indirectly, since that will prevent the keys from being discarded."