JuanseCraft
Boot Manager for Minecraft Java.
Technology and Settings
Patch Notes · v1.1
Eight new things in two batches, all inside the launcher. No need to download anything separately or install anything else.
- Enable and disable mods. One checkbox per mod, and the change applies
instantly — no save button. It's disabled by renaming the
.jar, the same convention used by Prism and CurseForge: a mod disabled from another launcher shows as disabled here too, and vice versa. - The launcher profile now has an understandable name. The Fabric installer
used to leave it as
fabric-loader-26.2; now it shows as Fabric 26.2 · JuanseCraft. And once it finishes installing, it lets you know you need to close and reopen the official launcher, which was the piece that was really missing. - Texture pack to gain FPS. Opaque leaves, invisible plants and flat water. It's generated on your PC, not downloaded from anywhere, and the same pack works for both old and new versions.
- Choose the garbage collector. G1, ZGC or Shenandoah. Only the ones actually supported by a Java you have installed show up, and if the version you're optimizing doesn't support it, G1 is used without you having to worry about it.
- Juansekill's server now comes pre-added. When you create a version it's added to your Multiplayer list. If you already had servers it's added at the end, and if you already had it added, nothing is touched.
- Warns about incompatible mods before you play. It detects duplicate mods, missing dependencies, versions that don't meet requirements, and conflicts declared by the mod authors themselves. Before, the game would just close after two seconds without saying anything. Extra mods are set aside, not deleted.
- World backups. One button in Settings → General. The zip is saved
outside
.minecraft, so nothing that happens in there can take it down with it. - Open the mods folder. The one for the active modset, which is the one you actually need when something goes wrong.
Quick Installation
- Download the file and unzip it to your desktop or preferred folder.
-
Run
JuanseCraft Java.exeto start. - Open Minecraft Java demo from the official launcher to get started.
- Wait for the demo to open and click on "Create Executable"
- An executable will be generated on your desktop, to launch the full game on that version!
📥 Download Launcher
Select your server. You will always get the latest version.
Your skin and cape on servers
You are the only one who sees your skin and cape. When you join a server, everyone else sees you as Steve — and you see them the same way. This is not a JuanseCraft bug: it is how Minecraft works.
Why it happens
In Minecraft your skin does not travel with you. When you join a server, every player's game asks Mojang's servers "which skin does this player have?". With a non-premium account nobody answers, so the default skin shows up.
What JuanseCraft does is install CustomSkinLoader and drop your PNG in your own folder. That is why you can see it. But the other player's game reads their folder, not yours.
How to fix it
If the server is yours
Install the SkinsRestorer plugin from your server panel (on Aternos
it is in the plugins section). From then on everyone sees your skin,
even players joining with the plain launcher and no mods. In game you use it with
/skin set <name>.
Heads up: this covers skins. Capes do not go through here.
If the server is not yours
Have the other person use JuanseCraft too. Sharing the same skin system means you see each other, capes included, without touching the server.
This is how non-premium launchers let their users see each other.
We are working on making this automatic: set your skin in JuanseCraft and everyone using the app sees it, with nothing to configure.
Frequently Asked Questions
I enabled a mod and it doesn't show up in the game
The change applies instantly, there's no save button. What the
manager does is rename the file: a disabled mod goes from something.jar
to something.jar.disabled. If you see it enabled in the list but not
in the game, it's almost always because Minecraft was open when you changed it:
close it and reopen it.
I installed Fabric and the profile doesn't show up in the launcher
You need to close the launcher completely and reopen it. It's not a bug: the official launcher only reads the profiles file once, on startup, and never checks it again. There's no way to force it to reload from outside. The profile is already created, you just won't see it until you reopen it.
Which garbage collector should I use?
If you're not sure, leave it on G1: it works everywhere. ZGC needs Java 15 or newer, 64-bit, and Shenandoah depends on who built that Java (Oracle doesn't include it; Adoptium and Red Hat do). The list only shows the ones supported by a Java you have installed, verified by actually running it, not guessed from the version number.
And if you pick one that the version you're optimizing doesn't support, G1 is used instead, no questions asked. That's on purpose: every Minecraft version ships its own Java, so picking ZGC just because 26.2 supports it would leave 1.16.5 unable to start.
Where do I download the texture pack from?
Nowhere: it's generated on your PC. It boosts FPS because normal leaves are drawn with transparency and the engine has to render everything behind every gap; with the opaque texture it just discards it. Tall grass alone is hundreds of transparent faces per chunk that don't cover anything.
Does it work for both old and new versions?
Yes, the same pack. Minecraft renamed the textures in 1.13, so both names are written, the old and the new one: the game uses whichever it recognizes and ignores the other. Tested on both ends, 1.16.5 and 26.2.
It warned me about incompatible mods. Does it delete them?
No. It sets them aside in a mods_desactivados folder,
and only if you choose "Set aside and play". You can also choose "Play anyway": the
diagnosis comes from what each mod declares, and it can be wrong.
Why does it generate a .bat file instead of opening the game?
Because that file is portable and you can inspect it: inside is the full command with the RAM, the Java, and the arguments that were chosen. You can move it, copy it to another PC, or open it with Notepad to see exactly what gets run. A launcher that launches the game internally doesn't let you see any of that.