Problems with Chronicle Map on Windows - memory-mapped-files

Question

I am trying to use ChronicleMap for my index structure, this seems to work fine on Linux but when I am running my JUnit test on Windows (which is my development environment), I keep getting an error: java.io.IOException: Unable to wait until the file is ready, likely the process which created the file crashed or hung for more than 1 minute.
Here's the code snippet that is problematic:
File file = new File(idxFullPath);
ChronicleMap<Integer, int[]> idx =
ChronicleMapBuilder.of(Integer.class, int[].class)
.averageValue(getSampleIdxList())
.entries(IDX_MAX_SIZE)
.createPersistedTo(file);
The following exception is thrown:
[2016-06-17 14:32:47.779] ERROR main com.mcm.op.persistence.Persistence ERR java.io.IOException: Unable to wait until the file is ready, likely the process which created the file crashed or hung for more than 1 minute
at net.openhft.chronicle.map.ChronicleMapBuilder.waitUntilReady(ChronicleMapBuilder.java:1520)
at net.openhft.chronicle.map.ChronicleMapBuilder.openWithExistingFile(ChronicleMapBuilder.java:1583)
at net.openhft.chronicle.map.ChronicleMapBuilder.createWithFile(ChronicleMapBuilder.java:1444)
at net.openhft.chronicle.map.ChronicleMapBuilder.createPersistedTo(ChronicleMapBuilder.java:1405)
at com.mcm.op.persistence.Persistence.initIdx(Persistence.java:131)
at com.mcm.op.persistence.Persistence.init(Persistence.java:177)
at com.mcm.op.persistence.PersistenceTest.initPersist(PersistenceTest.java:47)
at com.mcm.op.persistence.PersistenceTest.setUp(PersistenceTest.java:29)

Answer 1

Indeed, it is likely that the process which created the file has crashed, or stopped terminated debugging, or something like that.
If it's ok to have a fresh index from unit test-to-test runs, I recommend to try either delete the file at idxFullPath before creating a Chronicle Map, or randomize the mapping file via something like File.createTempFile(). In either case File.deleteOnExit() could appear to be helpful.
If you want to keep the index between unit test runs and always use the same file at idxFullPath for persistence, you could try to use builder.createOrRecoverPersistedTo() instead of plain createPersistedTo() map creation method. However this might slow down the map creation.