My Minecraft does not start

Put the summary of the bug you're having here

What I expected to happen was...:
Describe what you thought should happen here

What actually happened was...:
Describe what happened here

Steps to Reproduce:

--- Minecraft Crash Report ----
// This doesn't make any sense!

Time: 21.09.14 08:42
Description: Initializing game

java.lang.OutOfMemoryError: Java heap space
	at cue.a(SourceFile:363)
	at cue.a(SourceFile:255)
	at cua.b(SourceFile:130)
	at cua.a(SourceFile:77)
	at cxh.j(SourceFile:553)
	at cxh.a(SourceFile:139)
	at cxk.a(SourceFile:23)
	at cvt.a(SourceFile:99)
	at bsu.aj(SourceFile:437)
	at bsu.a(SourceFile:299)
	at net.minecraft.client.main.Main.main(SourceFile:120)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
	at cue.a(SourceFile:363)
	at cue.a(SourceFile:255)
	at cua.b(SourceFile:130)
	at cua.a(SourceFile:77)
	at cxh.j(SourceFile:553)
	at cxh.a(SourceFile:139)
	at cxk.a(SourceFile:23)
	at cvt.a(SourceFile:99)
	at bsu.aj(SourceFile:437)

-- Initialization --
Details:
Stacktrace:
	at bsu.a(SourceFile:299)
	at net.minecraft.client.main.Main.main(SourceFile:120)

-- System Details --
Details:
	Minecraft Version: 1.8
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_67, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 60826488 bytes (58 MB) / 523501568 bytes (499 MB) up to 523501568 bytes (499 MB)
	JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 1.8
	LWJGL: 2.9.1
	OpenGL: GeForce GT 330/PCI/SSE2 GL version 3.2.0, NVIDIA Corporation
	GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

	Using VBOs: No
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: [Sphax PureBDcraft 512x MC17.zip]
	Current Language: Deutsch (Deutschland)
	Profiler Position: N/A (disabled)