I was going to make a personal resource pack to modify some textures. So, I copied 18w15a jar extracted it etc. Anyways when I was launching mc to see whether or not I made the base template correctly I got this error "The game crashed whilst initializing game
Error: java.lang.IllegalStateException: Not a JSON Object: null" And this crash. "---- Minecraft Crash Report ----
// Who set us up the TNT?

Time: 4/16/18 3:27 PM
Description: Initializing game

java.lang.IllegalStateException: Not a JSON Object: null
at com.google.gson.JsonElement.getAsJsonObject(JsonElement.java:90)
at tl.a(SourceFile:72)
at tl.a(SourceFile:65)
at ud.a(SourceFile:35)
at ty.a(SourceFile:38)
at ua.a(SourceFile:32)
at cas.a(SourceFile:1189)
at cap.an(SourceFile:440)
at cap.a(SourceFile:369)
at net.minecraft.client.main.Main.main(SourceFile:141)

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

– Head –
Thread: Client thread
Stacktrace:
at com.google.gson.JsonElement.getAsJsonObject(JsonElement.java:90)
at tl.a(SourceFile:72)
at tl.a(SourceFile:65)
at ud.a(SourceFile:35)
at ty.a(SourceFile:38)
at ua.a(SourceFile:32)
at cas.a(SourceFile:1189)
at cap.an(SourceFile:440)

– Initialization –
Details:
Stacktrace:
at cap.a(SourceFile:369)
at net.minecraft.client.main.Main.main(SourceFile:141)

– System Details –
Details:
Minecraft Version: 18w15a
Operating System: Windows 10 (amd64) version 10.0
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 359876008 bytes (343 MB) / 436207616 bytes (416 MB) up to 1073741824 bytes (1024 MB)
JVM Flags: 8 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=16M
Launched Version: 18w15a
LWJGL: 3.1.2 build 29
OpenGL: Intel(R) HD Graphics 4200 GL version 4.3.0 - Build 20.19.15.4568, Intel
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: Yes
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs:
Current Language: ~_ERROR~ NullPointerException: null
Profiler Position: N/A (disabled)
CPU: 4x Intel(R) Core(TM) i3-4020Y CPU @ 1.50GHz"