[14:35:42] [Server thread/ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'sellall' in plugin IslandShop v1.2.3
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:47) ~[server.jar:git-Spigot-f39a89e-16dc575]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:149) ~[server.jar:git-Spigot-f39a89e-16dc575]
        at org.bukkit.craftbukkit.v1_15_R1.CraftServer.dispatchCommand(CraftServer.java:711) ~[server.jar:git-Spigot-f39a89e-16dc575]
        at net.minecraft.server.v1_15_R1.PlayerConnection.handleCommand(PlayerConnection.java:1657) ~[server.jar:git-Spigot-f39a89e-16dc575]
        at net.minecraft.server.v1_15_R1.PlayerConnection.a(PlayerConnection.java:1497) ~[server.jar:git-Spigot-f39a89e-16dc575]
        at net.minecraft.server.v1_15_R1.PacketPlayInChat.a(PacketPlayInChat.java:47) ~[server.jar:git-Spigot-f39a89e-16dc575]
        at net.minecraft.server.v1_15_R1.PacketPlayInChat.a(PacketPlayInChat.java:1) ~[server.jar:git-Spigot-f39a89e-16dc575]
        at net.minecraft.server.v1_15_R1.PlayerConnectionUtils.lambda$0(PlayerConnectionUtils.java:19) ~[server.jar:git-Spigot-f39a89e-16dc575]
        at net.minecraft.server.v1_15_R1.TickTask.run(SourceFile:18) [server.jar:git-Spigot-f39a89e-16dc575]
        at net.minecraft.server.v1_15_R1.IAsyncTaskHandler.executeTask(SourceFile:144) [server.jar:git-Spigot-f39a89e-16dc575]
        at net.minecraft.server.v1_15_R1.IAsyncTaskHandlerReentrant.executeTask(SourceFile:23) [server.jar:git-Spigot-f39a89e-16dc575]
        at net.minecraft.server.v1_15_R1.IAsyncTaskHandler.executeNext(SourceFile:118) [server.jar:git-Spigot-f39a89e-16dc575]
        at net.minecraft.server.v1_15_R1.MinecraftServer.aZ(MinecraftServer.java:917) [server.jar:git-Spigot-f39a89e-16dc575]
        at net.minecraft.server.v1_15_R1.MinecraftServer.executeNext(MinecraftServer.java:910) [server.jar:git-Spigot-f39a89e-16dc575]
        at net.minecraft.server.v1_15_R1.IAsyncTaskHandler.awaitTasks(SourceFile:127) [server.jar:git-Spigot-f39a89e-16dc575]
        at net.minecraft.server.v1_15_R1.MinecraftServer.sleepForTick(MinecraftServer.java:894) [server.jar:git-Spigot-f39a89e-16dc575]
        at net.minecraft.server.v1_15_R1.MinecraftServer.run(MinecraftServer.java:827) [server.jar:git-Spigot-f39a89e-16dc575]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_231]
Caused by: java.lang.NumberFormatException: For input string: "9,3"
        at sun.misc.FloatingDecimal.readJavaFormatString(Unknown Source) ~[?:1.8.0_231]
        at sun.misc.FloatingDecimal.parseDouble(Unknown Source) ~[?:1.8.0_231]
        at java.lang.Double.parseDouble(Unknown Source) ~[?:1.8.0_231]
        at me.aboodyy.islandshop.priceshandler.PriceGetter.getSell(PriceGetter.java:56) ~[?:?]
        at me.aboodyy.islandshop.utils.Utils.sellAll(Utils.java:131) ~[?:?]
        at me.aboodyy.islandshop.commands.SellAllCommand.onCommand(SellAllCommand.java:53) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45) ~[server.jar:git-Spigot-f39a89e-16dc575]
        ... 17 more