at com.mojang.authlib.GameProfile.hashCode(GameProfile.java:90)
at java.util.WeakHashMap.hash(Unknown Source)
at java.util.WeakHashMap.put(Unknown Source)
at org.apache.commons.lang3.builder.ToStringStyle.register(ToStringStyle.java:191)
at org.apache.commons.lang3.builder.ToStringStyle.appendClassName(ToStringStyle.java:1453)
at org.apache.commons.lang3.builder.ToStringStyle.appendStart(ToStringStyle.java:378)
at org.apache.commons.lang3.builder.ToStringBuilder.<init>(ToStringBuilder.java:263)
at org.apache.commons.lang3.builder.ToStringBuilder.<init>(ToStringBuilder.java:226)
at com.mojang.authlib.GameProfile.toString(GameProfile.java:97)
at ov.d(SourceFile:102)
at ov.a(SourceFile:93)
at ok.c(SourceFile:130)
at net.minecraft.server.MinecraftServer.v(SourceFile:555)
at nb.v(SourceFile:264)
at net.minecraft.server.MinecraftServer.u(SourceFile:471)
at net.minecraft.server.MinecraftServer.run(SourceFile:387)
at mr.run(SourceFile:657)
I had this problem but I fixed it by logging off of mine craft and starting the server without minecraft running.