Put the summary of the bug you're having here
What I expected to happen was...:
opening a new world
What actually happened was...:
It gave me an error
Steps to Reproduce:
1. log in
2. go onto single player
3. load a world
Related issues
Comments


Incomplete without a crash report from ([minecraft/crash-reports/crash-<DATE>-client.txt|http://hopper.minecraft.net/help/finding-minecraft-data-folder]
). Please attach it so that we can diagnose your issue.
For technical support please use the Mojang Support Center.

Is this what you need? ---- Minecraft Crash Report ----
// Would you like a cupcake?
Time: 6/25/14 10:29 AM
Description: Starting integrated server
java.lang.ExceptionInInitializerError
at net.minecraft.server.MinecraftServer.<init>(SourceFile:120)
at bvj.<init>(SourceFile:38)
at ban.a(SourceFile:1610)
at bdt.e(SourceFile:162)
at bdu.a(SourceFile:214)
at bcl.a(SourceFile:186)
at bdt.a(SourceFile:187)
at bof.b(SourceFile:852)
at ban.ak(SourceFile:801)
at ban.f(SourceFile:728)
at net.minecraft.client.main.Main.main(SourceFile:148)
Caused by: java.lang.IllegalStateException: failed to create a child event loop
at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:61)
at io.netty.channel.MultithreadEventLoopGroup.<init>(MultithreadEventLoopGroup.java:49)
at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:61)
at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:52)
at nb.<clinit>(SourceFile:31)
... 11 more
Caused by: io.netty.channel.ChannelException: failed to open a new selector
at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:128)
at io.netty.channel.nio.NioEventLoop.<init>(NioEventLoop.java:120)
at io.netty.channel.nio.NioEventLoopGroup.newChild(NioEventLoopGroup.java:87)
at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:57)
... 15 more
Caused by: java.io.IOException: Unable to establish loopback connection
at sun.nio.ch.PipeImpl$Initializer.run(Unknown Source)
at sun.nio.ch.PipeImpl$Initializer.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at sun.nio.ch.PipeImpl.<init>(Unknown Source)
at sun.nio.ch.SelectorProviderImpl.openPipe(Unknown Source)
at java.nio.channels.Pipe.open(Unknown Source)
at sun.nio.ch.WindowsSelectorImpl.<init>(Unknown Source)
at sun.nio.ch.WindowsSelectorProvider.openSelector(Unknown Source)
at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:126)
... 18 more
Caused by: java.net.SocketException: Unrecognized Windows Sockets error: 87: socket
at sun.nio.ch.Net.socket0(Native Method)
at sun.nio.ch.Net.serverSocket(Unknown Source)
at sun.nio.ch.ServerSocketChannelImpl.<init>(Unknown Source)
at sun.nio.ch.SelectorProviderImpl.openServerSocketChannel(Unknown Source)
at java.nio.channels.ServerSocketChannel.open(Unknown Source)
... 27 more
A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------
– Head –
Stacktrace:
at net.minecraft.server.MinecraftServer.<init>(SourceFile:120)
at bvj.<init>(SourceFile:38)
– Starting integrated server –
Details:
Level ID: New
Level Name: New
Stacktrace:
at ban.a(SourceFile:1610)
at bdt.e(SourceFile:162)
at bdu.a(SourceFile:214)
at bcl.a(SourceFile:186)
at bdt.a(SourceFile:187)
– Screen render details –
Details:
Screen name: bea
Mouse location: Scaled: (167, 104). Absolute: (670, 631)
Screen size: Scaled: (420, 263). Absolute: (1680, 1050). Scale factor of 4
Stacktrace:
at bof.b(SourceFile:852)
at ban.ak(SourceFile:801)
at ban.f(SourceFile:728)
at net.minecraft.client.main.Main.main(SourceFile:148)
– System Details –
Details:
Minecraft Version: 1.7.9
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.7.0_60, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 351516792 bytes (335 MB) / 391643136 bytes (373 MB) up to 954728448 bytes (910 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
Launched Version: 1.7.9
LWJGL: 2.9.1
OpenGL: AMD Radeon HD 6670 GL version 4.4.12874 Compatibility Profile Context 14.100.0.0, ATI Technologies Inc.
GL Caps: Using GL 1.3 multitexturing.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Anisotropic filtering is supported and maximum anisotropy is 16.
Shaders are available because OpenGL 2.1 is supported.
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs: [3D Models v1.9.1.zip]
Current Language: English (UK)
Profiler Position: N/A (disabled)
Vec3 Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Anisotropic Filtering: Off (1)

Duplicate of MC-34749. Something like your antivirus or firewall software is blocking the game.
This is a technical support issue; this site is for bug reports only. For technical support please use the Mojang Support Center.
1.7.7 is outdated. Please check to see if it occurs in 1.7.9