Crash

I am an old lady who has been playing MC for 3 years with my niece. I am not computer savvy, so I hope you can help me. 3 weeks ago, while playing, my screen went black and I could do nothing. I shut computer off and upon reloading MC, my world had reverted to about 2 years ago - tool inventory stayed current, but everything else did not + there are huge chunks that don't even load. I am unable to locate any saved worlds that aren't corrupted. I reinstalled both JAVA + MC and made sure there is 4 GB of RAM dedicated to MC. At first I received the long message from 7/27/19 as below, but now I receive this message and the game crashes within 1 minute:



ERROR

Game crashed

An unexpected issue occurred and the game has crashed. We are sorry for the inconvenience.




7/27/19

Exception ticking world



java.lang.OutOfMemoryError: Java heap space

at java.util.ArrayList.<init>(ArrayList.java:152)





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

---------------------------------------------------------------------------------------



-- Head --

Thread: Server thread

Stacktrace:

at java.util.ArrayList.<init>(ArrayList.java:152)

at com.google.common.collect.Lists.newArrayListWithCapacity(Lists.java:190)

at ik.a(SourceFile:62)

at id.a(SourceFile:438)

at id.a(SourceFile:81)

at id.a(SourceFile:438)

at id.a(SourceFile:81)

at io.a(SourceFile:113)

at io.a(SourceFile:78)

at io.a(SourceFile:74)

at byj.e(SourceFile:53)

at uw.g(SourceFile:816)

at uw.j(SourceFile:506)

at uw$$Lambda$2559/1212412641.get(Unknown Source)

at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1582)

at agq.h(SourceFile:144)

at agq.q(SourceFile:118)

at vi$a.q(SourceFile:550)

at vi.d(SourceFile:273)

at net.minecraft.server.MinecraftServer.aX(SourceFile:718)



-- Affected level --

Details:

All players: 1 total; [vl['Barbmir'/1915, l='Beach Home', x=727.26, y=64.00, z=864.42]]

Chunk stats: ServerChunkCache: 6238

Level dimension: minecraft:overworld

Level name: Beach Home

Level seed: -6214358314918949657

Level generator: ID 00 - default, ver 1. Features enabled: true

Level generator options: {}

Level spawn location: World: (188,64,232), Chunk: (at 12,4,8 in 11,14; contains blocks 176,0,224 to 191,255,239), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)

Level time: 102768618 game time, 1682041 day time

Level storage version: 0x04ABD - Anvil

Level weather: Rain time: 9009 (now: false), thunder time: 7379 (now: false)

Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: true

Stacktrace:

at net.minecraft.server.MinecraftServer.b(SourceFile:838)

at net.minecraft.server.MinecraftServer.a(SourceFile:774)

at eac.a(SourceFile:128)

at net.minecraft.server.MinecraftServer.run(SourceFile:642)

at java.lang.Thread.run(Thread.java:745)



-- System Details --

Details:

Minecraft Version: 1.14.4

Minecraft Version ID: 1.14.4

Operating System: Windows 8 (amd64) version 6.2

Java Version: 1.8.0_51, Oracle Corporation

Java VM Version: Java HotSpot(TM) 64-Bit Server VM