cdm/src/main/java/ucar/nc2/dataset/NetcdfDataset.java
static public synchronized void initNetcdfFileCache(
          int minElementsInMemory, int maxElementsInMemory, int hardLimit, int period) {
    netcdfFileCache = new ucar.nc2.util.cache.FileCache(
            "NetcdfFileCache ", minElementsInMemory, maxElementsInMemory, hardLimit, period);
  }
static public synchronized void initNetcdfFileCache(
          int minElementsInMemory, int maxElementsInMemory, int hardLimit, int period) {
    netcdfFileCache = new ucar.nc2.util.cache.FileCache(
            "NetcdfFileCache ", minElementsInMemory, maxElementsInMemory, hardLimit, period);
  }
Enable file caching. call this before calling acquireFile().
When application terminates, call NetcdfDataset.shutdown().

@param minElementsInMemory keep this number in the cache
@param maxElementsInMemory trigger a cleanup if it goes over this number.
@param hardLimit           if > 0, never allow more than this many elements. This causes a cleanup to be done in
the calling thread.
@param period              (secs) do periodic cleanups every this number of seconds.