bitcoinj/bitcoinj

Replace remaining usages of Guava's `BaseEncoding`

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#3982 opened on Jan 5, 2026

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EnhancementGuavagood first issue

Description

As of today we are using:

  • BaseEncoding.base16() -- can be replaced with our existing ByteUtils methods: formatHex and parseHex -- see PR #4011
  • BaseEncoding.base32() -- can be replaced with Bouncy Castle Base32 -- see PR #4012
  • BaseEncoding.base64() -- can be replaced with Bouncy Castle Base64 update: we should use java.util.Base64 -- see PR #4017

This helps implement Issue #2105 and although we want to also migrate away from Bouncy Castle (Issue #3912) migrating away from Guava is a short-term goal so I think it is OK to use Bouncy Castle (for now) to achieve it.

Update: for the Base32 and Base64 implementations, create methods that are identical (or very similar) to the Guava methods and place them in a class named BaseUtils in org.bitcoinj.core.internal.

I would also recommend doing this as a series of 3 PRs: one each for base16, base32, and base64.

Update: it looks like we can use java.util.Base64 as it is available in both Java 8 and Android API 26 (Android 8.0) -- see Android reference documentation: java.util.Base64

Contributor guide

Tech stack
java
Domain
backend
Issue type
refactor
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Basic JavaUnderstanding of Base64/Base32/Base16 encoding
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
The issue requires replacing Guava's BaseEncoding methods with alternatives: Base16 can be replaced with existing ByteUtils methods (see PR #4011), Base32 with Bouncy Castle's Base32 (PR #4012), and Base64 with java.util.Base64 (PR #4017). Start by reading the linked PRs to understand the pattern. Then, for each encoding, replace usages in the codebase and add corresponding methods in a new BaseUtils class under org.bitcoinj.core.internal. Ensure tests pass and no Guava dependency remains for these encodings. The issue suggests doing three separate PRs.