Using a code formatter should provide a guide to "make the code format itself"

[GreatGreenStar]

References Using a Code Formatter

Effectively rather than blocking when code isn't formatted, instead accept and format it.
for example (note this isn't "perfect" but should work for many java teams)
This one is what I'm currently working on for my setup, and thus includes a manual mode.

# This workflow uses actions that are not certified by GitHub.
# They are provided by a third-party and are governed by
# separate terms of service, privacy policy, and support
# documentation.
# This workflow will format a Java project with Gradle
# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-java-with-gradle

name: Spotless format check with Gradle
# Controls when the action will run. Triggers the workflow on push or pull request
# events
on:
  workflow_dispatch:
  pull_request:
  push:
    branches: [main]
# A workflow run is made up of one or more jobs that can run sequentially or in parallel
jobs:
  spotless-check:
    # The type of runner that the job will run on
    runs-on: ubuntu-22.04
    # Steps represent a sequence of tasks that will be executed as part of the job
    steps:
      # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
      - name: Checkout repo (Pull Request)
        #Checks if the event was trigged by a pull request, this step will be skipped if not.
        if: ${{ github.event_name == 'pull_request' }}
        uses: actions/checkout@v4
        with:
          #Sets up branch system properly per https://github.com/marketplace/actions/add-commit#working-with-prs
          repository: ${{ github.event.pull_request.head.repo.full_name }}
          ref: ${{ github.event.pull_request.head.ref }}
      - name: Checkout repo (Manually Run)
        #Only runs if triggered manually
        if: ${{github.event_name == 'workflow_dispatch' }}
        uses: actions/checkout@v4
      - name: Checkout repo (Push to main)
        #Only runs if triggered manually
        if: ${{github.event_name == 'push' }}
        uses: actions/checkout@v4
      - name: Setup Java
        uses: actions/setup-java@v4
        with:
          distribution: 'zulu'
          java-version: 17
      - name: Check with spotless
        id: spot-check
        run: ./gradlew spotlessCheck
      - name: Apply spotless
        if: ${{failure() }}
        run: ./gradlew spotlessApply
      - name: Commit changes
        if: ${{ failure() && steps.spot-check.conclusion == 'failure' }}
        uses: EndBug/add-and-commit@v9
        with:
          default_author: github_actions
          message: 'Formatted code using spotless.'