Constant crashes and laggy performance

Minecraft Crash Report ----
// Would you like a cupcake?

Time: 7/4/15 11:06 PM
Description: Tesselating block model

java.lang.OutOfMemoryError: Java heap space
at bgf.b(SourceFile:93)
at bgf.a(SourceFile:47)
at bgf.a(SourceFile:37)
at bgd.a(SourceFile:62)
at bht.b(SourceFile:176)
at bhp.a(SourceFile:78)
at bhp.run(SourceFile:38)
at java.lang.Thread.run(Thread.java:745)

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

– Head –
Stacktrace:
at bgf.b(SourceFile:93)

– Block model being tesselated –
Details:
Block: minecraft:dirt[snowy=false,variant=dirt]
Block location: World: (-362,81,149), Chunk: (at 6,5,5 in -23,9; contains blocks -368,0,144 to -353,255,159), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
Using AO: false
Stacktrace:
at bgf.a(SourceFile:47)
at bgf.a(SourceFile:37)

– Block being tesselated –
Details:
Block type: ID #3 (tile.dirt // agf)
Block data value: 0 / 0x0 / 0b0000
Block location: World: (-362,81,149), Chunk: (at 6,5,5 in -23,9; contains blocks -368,0,144 to -353,255,159), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
Stacktrace:
at bgd.a(SourceFile:62)

– Affected level –
Details:
Level name: MpServer
All players: 1 total; [bew['Skaer'/301, l='MpServer', x=-399.68, y=64.00, z=258.51]]
Chunk stats: MultiplayerChunkCache: 651, 651
Level seed: 0
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: -200.00,64.00,237.00 - World: (-200,64,237), Chunk: (at 8,4,13 in -13,14; contains blocks -208,0,224 to -193,255,239), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
Level time: 31196 game time, 31196 day time
Level dimension: 0
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Forced entities: 112 total; [vn['Creeper'/62980, l='MpServer', x=-360.50, y=27.00, z=316.50], uz['item.item.egg'/60678, l='MpServer', x=-425.75, y=64.00, z=243.09], vn['Creeper'/63495, l='MpServer', x=-414.50, y=17.00, z=209.50], wa['Skeleton'/62217, l='MpServer', x=-425.50, y=18.00, z=181.88], vo['Enderman'/63497, l='MpServer', x=-385.50, y=30.00, z=220.50], uz['item.item.egg'/60170, l='MpServer', x=-400.63, y=64.00, z=288.22], wc['Spider'/62220, l='MpServer', x=-429.03, y=18.00, z=179.97], tk['Bat'/62484, l='MpServer', x=-359.25, y=45.10, z=213.25], vn['Creeper'/62743, l='MpServer', x=-453.50, y=16.00, z=331.50], vn['Creeper'/62744, l='MpServer', x=-453.50, y=16.00, z=330.50], tv['Sheep'/57882, l='MpServer', x=-419.06, y=64.00, z=228.09], wa['Skeleton'/63770, l='MpServer', x=-419.50, y=32.00, z=191.50], wa['Skeleton'/63771, l='MpServer', x=-422.50, y=32.00, z=192.50], tv['Sheep'/58908, l='MpServer', x=-467.75, y=102.00, z=188.72], tk['Bat'/63261, l='MpServer', x=-342.63, y=17.81, z=217.69], vn['Creeper'/61470, l='MpServer', x=-436.50, y=18.00, z=185.50], tk['Bat'/62497, l='MpServer', x=-340.31, y=19.44, z=229.88], wa['Skeleton'/64035, l='MpServer', x=-441.19, y=33.00, z=252.69], tk['Bat'/61221, l='MpServer', x=-420.22, y=32.10, z=189.41], bew['Skaer'/301, l='MpServer', x=-377.44, y=65.00, z=242.76], uz['item.tile.dirt.default'/56371, l='MpServer', x=-373.66, y=66.00, z=238.84], tn['Chicken'/53, l='MpServer', x=-341.50, y=74.00, z=313.66], tk['Bat'/62011, l='MpServer', x=-387.03, y=18.00, z=205.41], tk['Bat'/61759, l='MpServer', x=-333.53, y=12.34, z=243.13], we['Zombie'/63809, l='MpServer', x=-446.94, y=25.00, z=226.34], tv['Sheep'/54082, l='MpServer', x=-361.16, y=63.00, z=205.88], we['Zombie'/63810, l='MpServer', x=-451.50, y=25.00, z=216.50], tv['Sheep'/54083, l='MpServer', x=-352.34, y=70.00, z=193.53], we['Zombie'/63811, l='MpServer', x=-451.50, y=25.00, z=218.50], tv['Sheep'/54084, l='MpServer', x=-362.81, y=70.00, z=194.75], we['Zombie'/64585, l='MpServer', x=-453.50, y=29.00, z=189.50], tv['Sheep'/56395, l='MpServer', x=-380.75, y=65.00, z=226.47], wa['Skeleton'/64588, l='MpServer', x=-446.50, y=28.00, z=195.03], wa['Skeleton'/64589, l='MpServer', x=-451.72, y=29.00, z=193.69], tv['Sheep'/8532, l='MpServer', x=-348.06, y=65.00, z=261.94], tv['Sheep'/8534, l='MpServer', x=-337.34, y=69.00, z=251.41], tv['Sheep'/8535, l='MpServer', x=-339.22, y=70.00, z=237.16], tn['Chicken'/54104, l='MpServer', x=-367.38, y=64.00, z=249.59], uz['item.item.egg'/64869, l='MpServer', x=-367.94, y=64.00, z=249.86], tv['Sheep'/10088, l='MpServer', x=-349.59, y=65.00, z=206.31], tv['Sheep'/10089, l='MpServer', x=-349.59, y=64.00, z=208.31], tv['Sheep'/54121, l='MpServer', x=-357.50, y=73.00, z=185.50], tv['Sheep'/10090, l='MpServer', x=-349.69, y=63.00, z=211.66], tv['Sheep'/54122, l='MpServer', x=-359.25, y=73.00, z=187.09], tk['Bat'/64372, l='MpServer', x=-436.75, y=39.00, z=264.78], bew['Skaer'/301, l='MpServer', x=-399.68, y=64.00, z=258.51], uz['item.item.rottenFlesh'/58498, l='MpServer', x=-442.66, y=63.00, z=282.84], tn['Chicken'/58499, l='MpServer', x=-432.50, y=64.00, z=272.50], we['Zombie'/61827, l='MpServer', x=-385.88, y=17.00, z=316.13], tn['Chicken'/58500, l='MpServer', x=-434.50, y=64.00, z=279.31], tn['Chicken'/58501, l='MpServer', x=-434.63, y=64.00, z=275.28], uz['item.item.egg'/58502, l='MpServer', x=-435.19, y=64.00, z=276.19], wc['Spider'/63878, l='MpServer', x=-456.50, y=23.00, z=210.50], vn['Creeper'/63879, l='MpServer', x=-455.94, y=23.00, z=208.53], tn['Chicken'/57480, l='MpServer', x=-400.50, y=64.00, z=280.66], tn['Chicken'/57481, l='MpServer', x=-401.50, y=66.00, z=295.50], tn['Chicken'/57482, l='MpServer', x=-409.72, y=67.00, z=294.50], we['Zombie'/61322, l='MpServer', x=-449.50, y=32.00, z=254.50], tn['Chicken'/57483, l='MpServer', x=-400.50, y=65.00, z=293.50], wa['Skeleton'/62091, l='MpServer', x=-413.13, y=38.00, z=227.47], uz['item.item.egg'/57485, l='MpServer', x=-401.91, y=65.00, z=294.06], we['Zombie'/61325, l='MpServer', x=-448.50, y=32.00, z=255.50], uz['item.item.egg'/57486, l='MpServer', x=-402.13, y=66.00, z=295.47], tv['Sheep'/57497, l='MpServer', x=-423.09, y=64.00, z=263.94], tv['Sheep'/58780, l='MpServer', x=-469.88, y=101.00, z=185.25], vn['Creeper'/64417, l='MpServer', x=-427.50, y=45.00, z=215.50], tn['Chicken'/57513, l='MpServer', x=-431.63, y=64.00, z=273.06], tv['Sheep'/58793, l='MpServer', x=-467.84, y=102.00, z=186.78], uz['item.item.egg'/57514, l='MpServer', x=-429.44, y=64.00, z=274.56], tv['Sheep'/58794, l='MpServer', x=-455.28, y=105.00, z=196.50], we['Zombie'/61611, l='MpServer', x=-403.94, y=44.00, z=249.31], wa['Skeleton'/62636, l='MpServer', x=-430.50, y=51.00, z=262.50], uz['item.item.egg'/60079, l='MpServer', x=-431.56, y=64.00, z=272.63], wc['Spider'/63919, l='MpServer', x=-456.31, y=22.09, z=218.28], uz['item.item.egg'/60080, l='MpServer', x=-339.50, y=70.00, z=231.38], tn['Chicken'/5041, l='MpServer', x=-339.44, y=70.00, z=231.63], uz['item.item.egg'/63677, l='MpServer', x=-417.88, y=63.00, z=244.22], wc['Spider'/62915, l='MpServer', x=-418.50, y=47.00, z=235.50], wa['Skeleton'/63684, l='MpServer', x=-400.50, y=45.00, z=198.50], tv['Sheep'/53963, l='MpServer', x=-353.16, y=65.00, z=272.03], tk['Bat'/61656, l='MpServer', x=-425.97, y=31.06, z=189.13], vn['Creeper'/63449, l='MpServer', x=-430.50, y=45.00, z=257.50], vn['Creeper'/63198, l='MpServer', x=-434.50, y=48.00, z=257.50], tk['Bat'/64478, l='MpServer', x=-460.34, y=21.66, z=209.56], wa['Skeleton'/64224, l='MpServer', x=-450.50, y=25.00, z=251.50], wa['Skeleton'/64225, l='MpServer', x=-451.50, y=25.00, z=251.50], tv['Sheep'/10210, l='MpServer', x=-339.94, y=70.00, z=235.91], tk['Bat'/64482, l='MpServer', x=-466.97, y=22.10, z=206.75], vn['Creeper'/63461, l='MpServer', x=-419.06, y=44.00, z=246.44], tn['Chicken'/57834, l='MpServer', x=-437.34, y=64.00, z=256.34], vn['Creeper'/63978, l='MpServer', x=-458.50, y=30.00, z=183.50], vn['Creeper'/64234, l='MpServer', x=-382.41, y=57.00, z=216.94], wc['Spider'/64746, l='MpServer', x=-410.41, y=44.09, z=246.69], tn['Chicken'/57835, l='MpServer', x=-428.72, y=64.00, z=245.56], vn['Creeper'/63979, l='MpServer', x=-449.50, y=30.00, z=187.50], vn['Creeper'/64235, l='MpServer', x=-384.03, y=57.00, z=217.59], tn['Chicken'/57836, l='MpServer', x=-424.84, y=64.00, z=244.72], wa['Skeleton'/63980, l='MpServer', x=-458.50, y=30.00, z=181.50], we['Zombie'/64236, l='MpServer', x=-380.50, y=57.00, z=217.50], tn['Chicken'/57837, l='MpServer', x=-433.44, y=64.00, z=244.69], uz['item.item.egg'/57839, l='MpServer', x=-428.31, y=64.00, z=245.91], we['Zombie'/63215, l='MpServer', x=-359.50, y=21.00, z=209.50], vn['Creeper'/64242, l='MpServer', x=-353.50, y=17.00, z=319.50], wa['Skeleton'/64243, l='MpServer', x=-351.72, y=17.00, z=320.66], wa['Skeleton'/64244, l='MpServer', x=-350.88, y=17.00, z=321.69], wa['Skeleton'/64245, l='MpServer', x=-352.50, y=17.00, z=319.50], tk['Bat'/63226, l='MpServer', x=-413.88, y=17.03, z=210.66], tn['Chicken'/4860, l='MpServer', x=-332.69, y=71.00, z=242.41], uz['item.item.egg'/52476, l='MpServer', x=-343.44, y=66.00, z=250.97], tn['Chicken'/4861, l='MpServer', x=-331.44, y=71.00, z=243.59], wd['Witch'/64765, l='MpServer', x=-332.50, y=15.00, z=192.50], tk['Bat'/63230, l='MpServer', x=-456.81, y=28.56, z=260.50]]
Retry entities: 0 total; []
Server brand: vanilla
Server type: Non-integrated multiplayer server
Stacktrace:
at bdb.a(SourceFile:309)
at ave.b(SourceFile:2293)
at bhp.run(SourceFile:44)
at java.lang.Thread.run(Thread.java:745)

– System Details –
Details:
Minecraft Version: 1.8.7
Operating System: Windows 8 (amd64) version 6.2
CPU: 2x Intel(R) Celeron(R) CPU N2840 @ 2.16GHz
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 2358688 bytes (2 MB) / 255066112 bytes (243 MB) up to 255066112 bytes (243 MB)
JVM Flags: 7 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M -Xmx256M
IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
Launched Version: 1.8.7
LWJGL: 2.9.4
OpenGL: ~_ERROR~ RuntimeException: No OpenGL context found in the current thread.
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: []
Current Language: English (US)
Profiler Position: N/A (disabled)