Question

With nio it is possible to map an existing file in memory. But is it possible to create it only in memory without file on the hard drive ?

I want to mimic the CreateFileMapping windows functions which allow you to write in memory.

Is there an equivalent system in Java ?

The goal is to write in memory in order for another program ( c ) to read it.

Answer 1

Have a look at the following. A file is created but this might be as close as your going to get.

MappedByteBuffer
MappedByteBuffer.load()
FileChannel
FileChannel.map()

Here is a snippet to try and get you started.

    filePipe = new File(tempDirectory, namedPipe.getName() + ".pipe");
    try {
        int pipeSize = 4096;
        randomAccessFile = new RandomAccessFile(filePipe, "rw");
        fileChannel = randomAccessFile.getChannel();
        mappedByteBuffer = fileChannel.map(FileChannel.MapMode.READ_WRITE, 0, pipeSize);
        mappedByteBuffer.load();
    } catch (Exception e) {
    ...