I created a world (1.8.1) planning to make a underground high-tech base(inspired by the penguins of Madagascar movie).I started digging a hole and planting down some redstone for the secret door,when for some random reason, I crash!I go back on again, a little of my process gone,as if the game had time-traveled back 8 seconds. A minute later I crash,again.Then the same thing happenes again.So I gave that up and decided to notify this bug to you guys.And so here I am.

One of the many crash reports:
[19:33:33] [Client thread/INFO]: Setting user: laughingiguana
[19:33:33] [Client thread/INFO]: (Session ID is token:db918a5a02f84091b9a04545573e9ce2:b8c4fd0f668f4dfc828b32905c120b57)
[19:33:36] [Client thread/INFO]: LWJGL Version: 2.9.1
[19:33:37] [Client thread/INFO]: Reloading ResourceManager: Default
[19:33:38] [Sound Library Loader/INFO]: Starting up SoundSystem...
[19:33:38] [Thread-6/INFO]: Initializing LWJGL OpenAL
[19:33:38] [Thread-6/INFO]: (The LWJGL binding of OpenAL. For more information, see http://www.lwjgl.org)
[19:33:38] [Thread-6/INFO]: OpenAL initialized.
[19:33:39] [Sound Library Loader/INFO]: Sound engine started
[19:33:41] [Client thread/INFO]: Created: 512x512 textures-atlas
[19:33:55] [Server thread/INFO]: Starting integrated minecraft server version 1.8.1
[19:33:55] [Server thread/INFO]: Generating keypair
[19:33:55] [Server thread/INFO]: Preparing start region for level 0
[19:33:56] [Server thread/INFO]: Preparing spawn area: 43%
[19:33:57] [Server thread/INFO]: Preparing spawn area: 89%
[19:33:58] [Server thread/INFO]: Changing view distance to 11, from 10
[19:33:58] [Server thread/INFO]: laughingiguana[local:E:34a6dad7] logged in with entity id 235 at (182.68550042579662, 55.78434930986885, 49.65515630524087)
[19:33:58] [Server thread/INFO]: laughingiguana joined the game
[19:34:28] [Server thread/INFO]: [laughingiguana: Set the time to 0]
[19:34:28] [Client thread/INFO]: [CHAT] Set the time to 0
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1. A fatal error has been detected by the Java Runtime Environment:
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2. EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x2bcb4a77, pid=6436, tid=4876
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3. JRE version: Java(TM) SE Runtime Environment (7.0_71-b14) (build 1.7.0_71-b14)
4. Java VM: Java HotSpot(TM) Client VM (24.71-b01 mixed mode windows-x86 )
5. Problematic frame:
6. C [ig4icd32.dll+0x104a77]
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7. Failed to write core dump. Minidumps are not enabled by default on client versions of Windows
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8. An error report file with more information is saved as:
9. C:\Users\Hunter\AppData\Roaming\.minecraft\hs_err_pid6436.log
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10. If you would like to submit a bug report, please visit:
11. http://bugreport.sun.com/bugreport/crash.jsp
12. The crash happened outside the Java Virtual Machine in native code.
13. See problematic frame for where to report the bug.
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    AL lib: (EE) alc_cleanup: 1 device not closed

-I also crash when there is a mob near me on a server(near=within view range)