After starting up a 14w07a server and playing for a while, it crashes.
The server crashes randomly with the same error every time:

---- Minecraft Crash Report ----
// Quite honestly, I wouldn't worry myself about that.

Time: 2/15/14 3:29 PM
Description: Exception in server tick loop

java.lang.NullPointerException: Exception in server tick loop
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)

A detailed walkthrough of the error, its code path and all known details is as follows:
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– System Details –
Details:
Minecraft Version: 14w07a
Operating System: Windows 8 (amd64) version 6.2
Java Version: 1.7.0_09, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 6504654944 bytes (6203 MB) / 8580825088 bytes (8183 MB) up to 8580825088 bytes (8183 MB)
JVM Flags: 2 total; -Xmx8G -Xms8G
IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
Profiler Position: N/A (disabled)
Player Count: 2 / 20; [oe['Raven2396'/23, l='CTF', x=439.84, y=108.93, z=16.41], oe['aopell'/46, l='CTF', x=599.18, y=89.00, z=-32.55]]
Is Modded: Unknown (can't tell)
Type: Dedicated Server (map_server.txt)