Every time i try to create a custom world i get this:

[11:34:42 INFO]: Client> [11:34:42] [Server thread/INFO]: Starting integrated minecraft server version 14w32d
[11:34:42 INFO]: Client> [11:34:42] [Server thread/INFO]: Generating keypair
[11:34:42 INFO]: Client> [11:34:42] [Server thread/INFO]: Converting map!
[11:34:42 INFO]: Client> [11:34:42] [Server thread/INFO]: Scanning folders...
[11:34:42 INFO]: Client> [11:34:42] [Server thread/INFO]: Total conversion count is 0
[11:34:42 INFO]: Client> [11:34:42] [Server thread/INFO]: Preparing start region for level 0
[11:34:44 INFO]: Client> [11:34:44] [Server thread/INFO]: Preparing spawn area: 3%
[11:34:45 INFO]: Client> [11:34:45] [Server thread/INFO]: Preparing spawn area: 5%
[11:34:46 INFO]: Client> [11:34:46] [Server thread/INFO]: Preparing spawn area: 6%
[11:34:47 INFO]: Client> [11:34:47] [Server thread/INFO]: Preparing spawn area: 7%
[11:34:48 INFO]: Client> [11:34:48] [Server thread/INFO]: Preparing spawn area: 9%
[11:34:51 INFO]: Client> [11:34:51] [Server thread/INFO]: Preparing spawn area: 11%
[11:34:52 INFO]: Client> [11:34:52] [Server thread/INFO]: Preparing spawn area: 13%
[11:34:53 INFO]: Client> [11:34:53] [Server thread/INFO]: Preparing spawn area: 15%
[11:34:54 INFO]: Client> [11:34:54] [Server thread/INFO]: Preparing spawn area: 17%
[11:34:55 INFO]: Client> [11:34:55] [Server thread/INFO]: Preparing spawn area: 18%
[11:34:56 INFO]: Client> [11:34:56] [Server thread/INFO]: Preparing spawn area: 20%
[11:34:57 INFO]: Client> [11:34:57] [Server thread/INFO]: Preparing spawn area: 22%
[11:34:58 INFO]: Client> [11:34:58] [Server thread/INFO]: Preparing spawn area: 23%
[11:34:59 INFO]: Client> [11:34:59] [Server thread/INFO]: Preparing spawn area: 25%
[11:35:00 INFO]: Client> [11:35:00] [Server thread/INFO]: Preparing spawn area: 27%
[11:35:01 INFO]: Client> [11:35:01] [Server thread/INFO]: Preparing spawn area: 28%
[11:35:02 INFO]: Client> [11:35:02] [Server thread/INFO]: Preparing spawn area: 30%
[11:35:08 INFO]: Client> [11:35:08] [Server thread/INFO]: Preparing spawn area: 32%
[11:35:09 INFO]: Client> [11:35:09] [Server thread/INFO]: Preparing spawn area: 34%
[11:35:10 INFO]: Client> [11:35:10] [Server thread/INFO]: Preparing spawn area: 35%
[11:35:11 INFO]: Client> [11:35:11] [Server thread/INFO]: Preparing spawn area: 37%
[11:35:12 INFO]: Client> [11:35:12] [Server thread/INFO]: Preparing spawn area: 38%
[11:35:13 INFO]: Client> [11:35:13] [Server thread/INFO]: Preparing spawn area: 40%
[11:35:14 INFO]: Client> [11:35:14] [Server thread/INFO]: Preparing spawn area: 41%
[11:35:16 INFO]: Client> [11:35:16] [Server thread/INFO]: Preparing spawn area: 43%
[11:35:17 INFO]: Client> [11:35:17] [Server thread/INFO]: Preparing spawn area: 45%
[11:35:18 INFO]: Client> [11:35:18] [Server thread/INFO]: Preparing spawn area: 46%
[11:35:19 INFO]: Client> [11:35:19] [Server thread/INFO]: Preparing spawn area: 48%
[11:35:20 INFO]: Client> [11:35:20] [Server thread/INFO]: Preparing spawn area: 49%
[11:35:21 INFO]: Client> [11:35:21] [Server thread/INFO]: Preparing spawn area: 50%
[11:35:22 INFO]: Client> [11:35:22] [Server thread/INFO]: Preparing spawn area: 52%
[11:35:23 INFO]: Client> [11:35:23] [Server thread/INFO]: Preparing spawn area: 53%
[11:35:25 INFO]: Client> [11:35:25] [Server thread/INFO]: Preparing spawn area: 55%
[11:35:26 INFO]: Client> [11:35:26] [Server thread/INFO]: Preparing spawn area: 55%
[11:35:27 INFO]: Client> [11:35:27] [Server thread/INFO]: Preparing spawn area: 57%
[11:35:33 INFO]: Client> [11:35:33] [Server thread/INFO]: Preparing spawn area: 57%
[11:35:34 INFO]: Client> [11:35:34] [Server thread/INFO]: Preparing spawn area: 59%
[11:35:35 INFO]: Client> [11:35:35] [Server thread/INFO]: Preparing spawn area: 60%
[11:35:36 INFO]: Client> [11:35:36] [Server thread/INFO]: Preparing spawn area: 62%
[11:35:37 INFO]: Client> [11:35:37] [Server thread/INFO]: Preparing spawn area: 64%
[11:35:38 INFO]: Client> [11:35:38] [Server thread/INFO]: Preparing spawn area: 64%
[11:35:39 INFO]: Client> [11:35:39] [Server thread/INFO]: Preparing spawn area: 66%
[11:35:41 INFO]: Client> [11:35:41] [Server thread/INFO]: Preparing spawn area: 67%
[11:35:47 INFO]: Client> [11:35:47] [Server thread/INFO]: Preparing spawn area: 69%
[11:35:48 INFO]: Client> [11:35:48] [Server thread/INFO]: Preparing spawn area: 71%
[11:35:52 INFO]: Client> [11:35:52] [Server thread/INFO]: Preparing spawn area: 71%
[11:35:53 INFO]: Client> [11:35:53] [Server thread/INFO]: Preparing spawn area: 73%
[11:35:57 INFO]: Client> [11:35:57] [Server thread/INFO]: Preparing spawn area: 74%
[11:35:58 INFO]: Client> [11:35:58] [Server thread/INFO]: Preparing spawn area: 76%
[11:36:03 INFO]: Client> [11:36:03] [Server thread/INFO]: Preparing spawn area: 76%
[11:36:04 INFO]: Client> [11:36:04] [Server thread/INFO]: Preparing spawn area: 78%
[11:36:08 INFO]: Client> [11:36:08] [Server thread/INFO]: Preparing spawn area: 78%
[11:36:15 INFO]: Client> [11:36:15] [Server thread/INFO]: Preparing spawn area: 80%
[11:36:20 INFO]: Client> [11:36:20] [Server thread/INFO]: Preparing spawn area: 81%
[11:36:25 INFO]: Client> [11:36:25] [Server thread/INFO]: Preparing spawn area: 83%
[11:36:30 INFO]: Client> [11:36:30] [Server thread/INFO]: Preparing spawn area: 84%
[11:36:34 INFO]: Client> [11:36:34] [Server thread/INFO]: Preparing spawn area: 84%
[11:36:39 INFO]: Client> [11:36:39] [Server thread/INFO]: Preparing spawn area: 85%
[11:36:44 INFO]: Client> [11:36:44] [Server thread/INFO]: Preparing spawn area: 85%
[11:36:50 INFO]: Client> [11:36:50] [Server thread/INFO]: Preparing spawn area: 86%
[11:36:54 INFO]: Client> [11:36:54] [Server thread/INFO]: Preparing spawn area: 86%
[11:36:59 INFO]: Client> [11:36:59] [Server thread/INFO]: Preparing spawn area: 86%
[11:37:03 INFO]: Client> [11:37:03] [Server thread/INFO]: Preparing spawn area: 87%
[11:37:07 INFO]: Client> [11:37:07] [Server thread/INFO]: Preparing spawn area: 87%
[11:37:16 INFO]: Client> [11:37:16] [Server thread/INFO]: Preparing spawn area: 87%
[11:37:21 INFO]: Client> [11:37:21] [Server thread/INFO]: Preparing spawn area: 88%
[11:37:26 INFO]: Client> [11:37:26] [Server thread/INFO]: Preparing spawn area: 88%
[11:37:34 INFO]: Client> [11:37:34] [Server thread/INFO]: Preparing spawn area: 88%
[11:37:56 INFO]: Client> [11:37:56] [Server thread/INFO]: Preparing spawn area: 88%
[11:38:59 INFO]: Client> [11:38:59] [Server thread/INFO]: Preparing spawn area: 88%
[11:39:44 INFO]: Client> [11:39:44] [Server thread/INFO]: Preparing spawn area: 88%
[11:40:02 INFO]: Client> [11:40:02] [Server thread/ERROR]: Encountered an unexpected exception
[11:40:02 INFO]: Client> java.lang.OutOfMemoryError: GC overhead limit exceeded
[11:40:02 INFO]: Client> at dt.a(SourceFile:52) ~[14w32d.jar:?]
[11:40:02 INFO]: Client> at bhx.b(SourceFile:63) ~[14w32d.jar:?]
[11:40:02 INFO]: Client> at bgo.a(SourceFile:468) ~[14w32d.jar:?]
[11:40:02 INFO]: Client> at qq.a(SourceFile:174) ~[14w32d.jar:?]
[11:40:02 INFO]: Client> at bfa.a(SourceFile:870) ~[14w32d.jar:?]
[11:40:02 INFO]: Client> at qq.c(SourceFile:104) ~[14w32d.jar:?]
[11:40:02 INFO]: Client> at net.minecraft.server.MinecraftServer.j(SourceFile:314) ~[14w32d.jar:?]
[11:40:02 INFO]: Client> at cxz.a(SourceFile:111) ~[14w32d.jar:?]
[11:40:02 INFO]: Client> at cxz.h(SourceFile:127) ~[14w32d.jar:?]
[11:40:02 INFO]: Client> at net.minecraft.server.MinecraftServer.run(SourceFile:416) [14w32d.jar:?]
[11:40:02 INFO]: Client> at java.lang.Thread.run(Unknown Source) [?:1.7.0_45]
[11:40:34 INFO]: Client> [11:40:34] [Server thread/INFO]: Stopping server
[11:40:34 INFO]: Client> [11:40:34] [Server thread/INFO]: Saving players
[11:40:34 INFO]: Client> [11:40:34] [Server thread/INFO]: Saving worlds
[11:40:34 INFO]: Client> [11:40:34] [Server thread/INFO]: Saving chunks for level 'Copy o Copy o Copy o Copy o'/Overworld
[11:41:16 INFO]: Client> [11:41:16] [Server thread/ERROR]: Exception stopping the server
[11:41:16 INFO]: Client> java.lang.OutOfMemoryError: GC overhead limit exceeded
[11:41:16 INFO]: Client> at nz.toString(SourceFile:51) ~[14w32d.jar:?]
[11:41:16 INFO]: Client> at bfr.a(SourceFile:266) ~[14w32d.jar:?]
[11:41:16 INFO]: Client> at bfr.a(SourceFile:113) ~[14w32d.jar:?]
[11:41:16 INFO]: Client> at qq.b(SourceFile:160) ~[14w32d.jar:?]
[11:41:16 INFO]: Client> at qq.a(SourceFile:203) ~[14w32d.jar:?]
[11:41:16 INFO]: Client> at qr.a(SourceFile:766) ~[14w32d.jar:?]
[11:41:16 INFO]: Client> at net.minecraft.server.MinecraftServer.a(SourceFile:359) ~[14w32d.jar:?]
[11:41:16 INFO]: Client> at net.minecraft.server.MinecraftServer.q(SourceFile:382) ~[14w32d.jar:?]
[11:41:16 INFO]: Client> at cxz.q(SourceFile:303) ~[14w32d.jar:?]
[11:41:16 INFO]: Client> at net.minecraft.server.MinecraftServer.run(SourceFile:478) [14w32d.jar:?]
[11:41:16 INFO]: Client> at java.lang.Thread.run(Unknown Source) [?:1.7.0_45]
[11:41:16 INFO]: Client> Exception in thread "Server thread" java.lang.OutOfMemoryError: GC overhead limit exceeded
[11:41:16 INFO]: Client> at java.util.Arrays.copyOf(Unknown Source)
[11:41:16 INFO]: Client> at sun.misc.IOUtils.readFully(Unknown Source)
[11:41:16 INFO]: Client> at java.util.jar.JarFile.getBytes(Unknown Source)
[11:41:16 INFO]: Client> at java.util.jar.JarFile.getManifestFromReference(Unknown Source)
[11:41:16 INFO]: Client> at java.util.jar.JarFile.getInputStream(Unknown Source)
[11:41:16 INFO]: Client> at sun.misc.URLClassPath$JarLoader$2.getInputStream(Unknown Source)
[11:41:16 INFO]: Client> at sun.misc.Resource.cachedInputStream(Unknown Source)
[11:41:16 INFO]: Client> at sun.misc.Resource.getByteBuffer(Unknown Source)
[11:41:16 INFO]: Client> at java.net.URLClassLoader.defineClass(Unknown Source)
[11:41:16 INFO]: Client> at java.net.URLClassLoader.access$100(Unknown Source)
[11:41:16 INFO]: Client> at java.net.URLClassLoader$1.run(Unknown Source)
[11:41:16 INFO]: Client> at java.net.URLClassLoader$1.run(Unknown Source)
[11:41:16 INFO]: Client> at java.security.AccessController.doPrivileged(Native Method)
[11:41:16 INFO]: Client> at java.net.URLClassLoader.findClass(Unknown Source)
[11:41:16 INFO]: Client> at java.lang.ClassLoader.loadClass(Unknown Source)
[11:41:16 INFO]: Client> at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
[11:41:16 INFO]: Client> at java.lang.ClassLoader.loadClass(Unknown Source)
[11:41:16 INFO]: Client> at net.minecraft.server.MinecraftServer.run(SourceFile:464)
[11:41:16 INFO]: Client> at java.lang.Thread.run(Unknown Source)

I dont know if its just me but can you fix it? thank you.