Hero Studios

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J2B MC

Recreate Minecraft Bedrock Edition inside your Java world — one button. All the mechanics, all the bugs, everything Bedrockified.

J2B MC 3.2.3

26.x builds are blocked upstream (no mappings).

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BuildFileSizeSHA-256Get
1.21.11 j2bmc-3.2.3-1.21.11.jar 0.46 MB b8e2d91a4ec2… JAR
1.21.10 j2bmc-3.2.1-1.21.10.jar 0.33 MB f96d4a128a05… JAR
1.21.9 j2bmc-3.2.1-1.21.9.jar 0.33 MB 291af3c3d683… JAR
1.21.8 j2bmc-3.2.1-1.21.8.jar 0.33 MB a1035cd40cfa… JAR
1.21.7 j2bmc-3.2.1-1.21.7.jar 0.33 MB 1c1cab776ed7… JAR
1.21.6 j2bmc-3.2.1-1.21.6.jar 0.33 MB 6f0c6c8f080b… JAR
1.21.5 j2bmc-3.2.1-1.21.5.jar 0.33 MB 6de02a64ad91… JAR
1.21.4 j2bmc-3.2.1-1.21.4.jar 0.33 MB 2b90a4159ea7… JAR
1.21.3 j2bmc-3.2.1-1.21.3.jar 0.33 MB 002b01992ac5… JAR
1.21.2 j2bmc-3.2.1-1.21.2.jar 0.33 MB 9f6156a1995d… JAR
1.21.1 j2bmc-3.2.1-1.21.1.jar 0.32 MB fb658afab3d6… JAR
1.21 j2bmc-3.2.1-1.21.jar 0.32 MB f9519215d2ca… JAR

Click a SHA-256 hash to copy it, then verify your download matches.

Downloads are provided under the HBBML license. Install instructions are in the documentation. Always verify the SHA-256 checksum of downloaded files.

Version history & known issues

All versions, every note

Every release of J2B MC with its warnings and known errors. The table above lets you download any version's files.

3.2.3 2026-11-03 Download files →

Account linked: shared session, plan and progress

  • Account client reads Hero Client's shared session — sign in once, both mods are linked
  • Config screen shows live plan status (username, plan, sessions/day, toggle unlocks)
  • Progress milestones: launch, Bedrock connect, world bedrockified, UI toggles, resource pack conversion
  • Plan entitlements from the shared source
  • 80 automated tests passing
3.2.2 2026-11-03 Download files →

World sync, resource packs & performance

  • World Sync Engine: biome, weather, time and entity synchronisation from Bedrock sessions
  • Resource pack translation: Bedrock textures, models and sounds converted to Java format
  • UI parity toggles: health bars, inventory, crafting, hotbar, chat and scoreboard
  • Performance pass: chunk optimiser, entity culler, packet batcher, memory pool
  • Birthday easter egg removed from mainline (kept on the birthday-2026 branch)
  • 80 automated tests passing
3.2.1 2026-10-16 Download files →

Full compatibility + protocol fixes

  • All 12 MC versions (1.21-1.21.11) now compile natively
  • 161 Bedrock mechanics across 13 phases
  • Fixed RakNet ACK, split packets, reliability, keepalive
  • Fixed Bedrock crypto (server salt, HKDF-SHA256)
  • Fixed JWT chain wire format
  • Added RequestChunkRadius + SetLocalPlayerAsInitialized packets
  • Added 400+ vanilla block/item/entity mappings
  • Added /j2b report command
  • Added UI config toggles (HUD, coordinates, chat, hotbar)
  • Fixed world importer zip-slip vulnerability
  • Added 10 protocol unit tests
Online Bedrock auth is still being verified against real servers
26.x builds are blocked upstream (no mappings)
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