Problem with special characters encoding

[Axer22]

I have this error when I have any special characters like "ą" or "»" in language.yml file.

[22:01:00] [Server thread/ERROR]: Error occurred while enabling PreciousStones v1.16.1.12 (Is it up to date?)
org.yaml.snakeyaml.error.YAMLException: java.nio.charset.MalformedInputException: Input length = 1
	at org.yaml.snakeyaml.reader.StreamReader.update(StreamReader.java:218) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.reader.StreamReader.ensureEnoughData(StreamReader.java:176) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.reader.StreamReader.peek(StreamReader.java:136) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.scanner.ScannerImpl.scanPlain(ScannerImpl.java:1987) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.scanner.ScannerImpl.fetchPlain(ScannerImpl.java:1044) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.scanner.ScannerImpl.fetchMoreTokens(ScannerImpl.java:399) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.scanner.ScannerImpl.checkToken(ScannerImpl.java:227) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.parser.ParserImpl$ParseBlockMappingKey.produce(ParserImpl.java:558) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.parser.ParserImpl.peekEvent(ParserImpl.java:158) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.parser.ParserImpl.checkEvent(ParserImpl.java:148) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.composer.Composer.composeMappingNode(Composer.java:235) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.composer.Composer.composeNode(Composer.java:162) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.composer.Composer.getNode(Composer.java:95) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.composer.Composer.getSingleNode(Composer.java:119) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.constructor.BaseConstructor.getSingleData(BaseConstructor.java:150) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.Yaml.loadFromReader(Yaml.java:472) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.Yaml.load(Yaml.java:411) ~[patched_1.16.4.jar:git-Purpur-952]
	at net.sacredlabyrinth.Phaed.PreciousStones.managers.LanguageManager.loadFile(LanguageManager.java:61) ~[?:?]
	at net.sacredlabyrinth.Phaed.PreciousStones.managers.LanguageManager.check(LanguageManager.java:44) ~[?:?]
	at net.sacredlabyrinth.Phaed.PreciousStones.managers.LanguageManager.load(LanguageManager.java:35) ~[?:?]
	at net.sacredlabyrinth.Phaed.PreciousStones.managers.LanguageManager.<init>(LanguageManager.java:30) ~[?:?]
	at net.sacredlabyrinth.Phaed.PreciousStones.PreciousStones.onEnable(PreciousStones.java:126) ~[?:?]
	at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:263) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:380) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:483) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.bukkit.craftbukkit.v1_16_R3.CraftServer.enablePlugin(CraftServer.java:501) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.bukkit.craftbukkit.v1_16_R3.CraftServer.enablePlugins(CraftServer.java:415) ~[patched_1.16.4.jar:git-Purpur-952]
	at net.minecraft.server.v1_16_R3.MinecraftServer.loadWorld(MinecraftServer.java:466) ~[patched_1.16.4.jar:git-Purpur-952]
	at net.minecraft.server.v1_16_R3.DedicatedServer.init(DedicatedServer.java:249) ~[patched_1.16.4.jar:git-Purpur-952]
	at net.minecraft.server.v1_16_R3.MinecraftServer.w(MinecraftServer.java:937) ~[patched_1.16.4.jar:git-Purpur-952]
	at net.minecraft.server.v1_16_R3.MinecraftServer.lambda$a$0(MinecraftServer.java:175) ~[patched_1.16.4.jar:git-Purpur-952]
	at java.lang.Thread.run(Thread.java:832) [?:?]
Caused by: java.nio.charset.MalformedInputException: Input length = 1
	at java.nio.charset.CoderResult.throwException(CoderResult.java:274) ~[?:?]
	at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:352) ~[?:?]
	at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:188) ~[?:?]
	at java.io.InputStreamReader.read(InputStreamReader.java:181) ~[?:?]
	at org.yaml.snakeyaml.reader.UnicodeReader.read(UnicodeReader.java:125) ~[patched_1.16.4.jar:git-Purpur-952]
	at org.yaml.snakeyaml.reader.StreamReader.update(StreamReader.java:183) ~[patched_1.16.4.jar:git-Purpur-952]
	... 31 more
[22:01:00] [Server thread/INFO]: [PreciousStones] Disabling PreciousStones v1.16.1.12

[Axer22]

When I set options.setAllowUnicode(false); in 74 line of LanguageManager class, the problem dissapeared. There must be something with saveFile() method in that class.

[DiaxManPl]

Try running server with -Dfile.encoding=UTF-8 option