cdm/src/main/java/ucar/nc2/util/DiskCache.java
static void make(String filename) throws IOException {
    File want = DiskCache.getCacheFile(filename);
    System.out.println("make=" + want.getPath() + "; exists = " + want.exists());
    if (!want.exists()) {
      boolean ret = want.createNewFile();
      assert ret;
    }
    System.out.println(" canRead= " + want.canRead() + " canWrite = " + want.canWrite() + " lastMod = " + new Date(want.lastModified()));
    System.out.println(" original=" + filename);
  }
static void make(String filename) throws IOException {
    File want = DiskCache.getCacheFile(filename);
    System.out.println("make=" + want.getPath() + "; exists = " + want.exists());
    if (!want.exists()) {
      boolean ret = want.createNewFile();
      assert ret;
    }
    System.out.println(" canRead= " + want.canRead() + " canWrite = " + want.canWrite() + " lastMod = " + new Date(want.lastModified()));
    System.out.println(" original=" + filename);
  }
debug

@param filename look for this file
@throws java.io.IOException if read error