Games : every time i get on minecraft it says this

[18:56:38] [Client thread/INFO]: Setting user: NamiNoKaze
[18:56:38] [Client thread/INFO]: (Session ID is token:90af3f3ac14f4a98b141e05bac0c6c23:31fb059e9b864498919f8ed7772b2e89)
Exception in thread "Client thread" com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1
    at com.google.gson.Gson.fromJson(Gson.java:815)
    at com.google.gson.Gson.fromJson(Gson.java:768)
    at lu.b(SourceFile:151)
    at lu.<init>(SourceFile:43)
    at net.minecraft.server.MinecraftServer.<init>(SourceFile:155)
    at bpp.<init>(SourceFile:41)
    at avf.<init>(SourceFile:293)
    at net.minecraft.client.main.Main.main(SourceFile:124)
Caused by: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1
    at com.google.gson.stream.JsonReader.beginArray(JsonReader.java:338)
    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:79)
    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:60)
    at com.google.gson.Gson.fromJson(Gson.java:803)
    ... 7 more
Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release