Character encoding

FreeMind stores Unicode characters as XML character entities into mind map files.

Reading of UTF-8 encoded mind map files is supported, with or without UTF-8 byte order mark (BOM).

Reading of UTF-32BE, UTF-32LE, UTF-16BE and UTF-16LE seem to be all supported provided the mind map starts with byte order mark (BOM).

Writing of UTF-8 is probably not supported; there was a feature request for this.

FreeMind does not write any BOM natively; given it writes XML character entities, it would make no sense.

Implementation

Reading:

Class FileReaderCreator in MindMapMapModel uses UTF-8 as the character encoding: 'return new UnicodeReader(new FileInputStream(mFile), "UTF-8");'
The above class is instantiated in MindMapMapModel.loadTree(final File) method.
Which is called from MindMapMapModel.load(File file).
Class UnicodeReader determines the encoding from byte order mark (BOM), if any; it seems to take the passed-in "UTF-8" in case there is no BOM.

Writing:

XMLElement.writeEncoded() encodes Unicode points such that unicode < 32 or unicode > 126 as XML character entities.

Links:

There is no or little support for XML declaration at the top of the mind map file; to be tested and clarified.
Probably no writing in UTF-8, as per above.