Clearcutt Catalog
Reference Catalog
OpenJDK
Java 21 · Slim · Slim runtime

clearcutt-java21 : slim

Runtime tier — language runtime plus minimal troubleshooting binaries.

v0.12.2 amd64arm64 Status: active Support: LTS Prod Allowed Signature: Verified Provenance: Verified SBOM: Verified Vulnerability scan: Observed Tests: Verified Evidence overlays listed
Multi-arch Manifest Digest:
sha256:558cb5c5396a2dcb350cb0494abf54d718d36e08eb9adfa1af0e6efc889396e1

Published Sat, 04 Jul 2026 17:29:57 GMT

Last Rebuilt Tue, 04 Aug 2026 07:08:33 GMT

Scan data observed
1

About this Image & Usage

Explore container capabilities, common use cases, and integration blueprints.

Capabilities & Guarantees

This Java Runtime Environment (JRE) image delivers a Zulu OpenJDK JRE 21 environment equipped with a restricted BusyBox debugging shell. It is designed for lightweight hosting with basic shell inspection capabilities.

Common Use Cases

  • Deploying standard enterprise web applications (Spring Boot, Quarkus, Micronaut)
  • Running microservices that require runtime hooks or staging environment diagnostics
  • Hosting modular JRE processes with optimized memory configurations

Runtime Security & Execution Contract

Shell PresenceYes (BusyBox/Bash)
Package ManagerNo (Absent)
Secure UID OperatorUID 10001
Production TierYes (Allowed)
CA CertificatesPresent / Active
Timezone DataPresent / Active

Developer blueprints

Copy pre-configured code structures to accelerate deployment pipelines.

Dockerfile dockerfile
# Stage 1: Build the Maven application inside Java JDK dev builder
FROM ghcr.io/northcutted/clearcutt/clearcutt-java21:v0.12.2-dev AS builder
WORKDIR /app

COPY pom.xml .
COPY src ./src
RUN mvn clean package -DskipTests

# Stage 2: Hardened runner stage (distroless or slim Java JRE runtime)
FROM ghcr.io/northcutted/clearcutt/clearcutt-java21:v0.12.2-slim
WORKDIR /app

# Copy JRE-optimized JAR file
COPY --from=builder /app/target/*.jar ./app.jar

# Run JRE application as secure non-root operator
USER 10001:10001
CMD ["java", "-jar", "app.jar"]

If your organization mandates a certified base OS (like Red Hat UBI, Amazon Linux, or Ubuntu Pro) for compliance, you can stack ClearCutt's RPATH-bound /nix/store closure directly on top without modifying base layers or bundled agents.

flake.overlay.nix nix
{
  description = "ClearCutt java21 grafted onto a mandated base";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    clearcutt.url = "github:northcutted/clearcutt/v0.12.2?dir=core";
  };

  outputs = { self, nixpkgs, clearcutt }:
    let
      system = "x86_64-linux";
      pkgs = import nixpkgs { inherit system; };
      mandatedBase = pkgs.dockerTools.pullImage {
        imageName = "registry.access.redhat.com/ubi9/ubi-minimal";
        imageDigest = "sha256:REPLACE_WITH_PINNED_BASE_DIGEST";
        sha256 = "sha256-REPLACE_WITH_NIX_PREFETCH_DOCKER_HASH";
      };
    in {
      packages.${system}.overlayImage = clearcutt.lib.graftOntoBase {
        inherit system;
        fromImage = mandatedBase;
        runtime = "java21";
        tier = "slim";
        name = "acme-java21-ubi";
        tag = "v0.12.2";
      };
    };
}

# Build: nix build .#packages.x86_64-linux.overlayImage
# Then prove the grafted runtime is byte-identical to the native runtime:
# clearcutt overlay verify \
#   --runtime-archive clearcutt-java21.tar \
#   --grafted-archive result \
#   --runtime-ref ghcr.io/northcutted/clearcutt/clearcutt-java21:v0.12.2-slim@sha256:... \
#   --grafted-ref ghcr.io/acme/java21-ubi:v0.12.2@sha256:... \
#   --target java21-slim \
#   --output-predicate
flake.nix nix
# Run an interactive local dev shell with the exact same remediated Zulu JDK:
$ nix shell github:northcutted/clearcutt/v0.12.2?dir=core#clearcuttJava21-native

# Or declare inside your local flake.nix:
{
  inputs.clearcutt.url = "github:northcutted/clearcutt/v0.12.2?dir=core";
  outputs = { self, nixpkgs, clearcutt }: {
    devShells.x86_64-linux.default = let
      pkgs = import nixpkgs {
        system = "x86_64-linux";
        overlays = [ clearcutt.overlays.default ];
      };
    in pkgs.mkShell {
      buildInputs = [ pkgs.clearcuttJava21 ];
    };
  };
}
layer.nix nix
# Layer a custom JAR application declaratively in your Nix configuration
pkgs.dockerTools.buildImage {
  name = "custom-java-microservice";
  tag = "latest";
  
  # Layer on top of ClearCutt's JRE base
  fromImage = clearcutt-base-image;

  copyToRoot = pkgs.buildEnv {
    name = "image-root";
    paths = [
      pkgs.zlib           # Layer in native dynamic libraries
      java-app-package    # Include your packaged JAR launcher
    ];
    pathsToLink = [ "/bin" "/lib" ];
  };

  config = {
    Cmd = [ "/bin/java-app" ];
    User = "10001:10001";
  };
}

Pull & Run Workspace

Select your preferred container engine or deployment platform target.

Pull by multi-arch digest (Recommended, Secure)

docker pull ghcr.io/northcutted/clearcutt/clearcutt-java21@sha256:558cb5c5396a2dcb350cb0494abf54d718d36e08eb9adfa1af0e6efc889396e1

Pinned to release

docker pull ghcr.io/northcutted/clearcutt/clearcutt-java21:v0.12.2-slim

Quick pull (rolling)

docker pull ghcr.io/northcutted/clearcutt/clearcutt-java21:slim

Hardened docker run

docker run --rm \
  --read-only \
  --cap-drop=ALL \
  --security-opt no-new-privileges \
  --user 10001:10001 \
  --tmpfs /tmp:mode=1777 \
  ghcr.io/northcutted/clearcutt/clearcutt-java21:v0.12.2-slim

Pull by multi-arch digest (Recommended, Secure)

podman pull ghcr.io/northcutted/clearcutt/clearcutt-java21@sha256:558cb5c5396a2dcb350cb0494abf54d718d36e08eb9adfa1af0e6efc889396e1

Pinned to release

podman pull ghcr.io/northcutted/clearcutt/clearcutt-java21:v0.12.2-slim

Quick pull (rolling)

podman pull ghcr.io/northcutted/clearcutt/clearcutt-java21:slim

Hardened podman run

podman run --rm \
  --read-only \
  --cap-drop=ALL \
  --security-opt no-new-privileges \
  --user 10001:10001 \
  --tmpfs /tmp:mode=1777 \
  ghcr.io/northcutted/clearcutt/clearcutt-java21:v0.12.2-slim
docker-compose.yml yaml
services:
  app:
    image: ghcr.io/northcutted/clearcutt/clearcutt-java21:v0.12.2-slim
    read_only: true
    user: "10001:10001"
    security_opt:
      - no-new-privileges:true
    cap_drop:
      - ALL
    tmpfs:
      - /tmp:mode=1777
pod.yaml yaml
apiVersion: v1
kind: Pod
metadata:
  name: clearcutt-java21
spec:
  automountServiceAccountToken: false
  securityContext:
    runAsNonRoot: true
    runAsUser: 10001
    runAsGroup: 10001
    seccompProfile: { type: RuntimeDefault }
  containers:
    - name: app
      image: ghcr.io/northcutted/clearcutt/clearcutt-java21:v0.12.2-slim
      imagePullPolicy: IfNotPresent
      securityContext:
        readOnlyRootFilesystem: true
        allowPrivilegeEscalation: false
        capabilities: { drop: ["ALL"] }
      volumeMounts:
        - { name: tmp, mountPath: /tmp }
  volumes:
    - { name: tmp, emptyDir: { medium: Memory } }
flake.nix nix
{
  inputs.clearcutt.url = "github:northcutted/clearcutt/v0.12.2?dir=core";
  outputs = { self, nixpkgs, clearcutt }: {
    devShells.x86_64-linux.default = let
      pkgs = import nixpkgs {
        system = "x86_64-linux";
        overlays = [ clearcutt.overlays.default ];
      };
    in pkgs.mkShell {
      buildInputs = [ pkgs.clearcuttJava21 ];
    };
  };
}
2

Verify & Audit Compliance

Inspect catalog evidence, run registry-side verification where evidence exists, and review vulnerability gates.

Provenance & signatures

Cryptographically audit OCI identity claims and supply chain gating artifacts.

raw in-toto JSONL

Cryptographic Proof

CATALOG REPORTS SIGNATURE
Signing Workflow release.yml
Workflow Ref refs/heads/main
OIDC Issuer token.actions.githubusercontent.com
OIDC Certificate Subject
https://github.com/northcutted/clearcutt/.github/workflows/release.yml@refs/heads/main

Supply Chain Provenance

PROVENANCE RECORDED 3
Build Type GitHub Actions Workflow
Predicate Schema SLSA Provenance v1.0
Source Material github.com/northcutted/clearcutt
Commit SHA 7211d7e ↗
Signed provenance record: Passed

Compilation & Tests

TESTS PASSED
Closure Purity (distroless boundary)
Runtime-Patch Completeness (crypto identity allowlist)
Gating timestamp: 2026-07-04T16:53

Attestations

4 kinds of evidence for this image. The counts are how many times each was independently signed into the public transparency log — not how many distinct artifacts exist.

22 signed records
Subject ghcr.io/northcutted/clearcutt/clearcutt-java21 Digest sha256:558cb5c5396a... index · amd64+arm64 Signed By release.yml @ main keyless ✓
Two ways to verify — pick the ecosystem you know
cosign · OCI Attestation lives with the image in the registry. Verify with cosign verify-attestation.
gh CLI · GitHub GitHub first-party attestation. Verify with gh attestation verify.

The subject above is the multi-arch index (amd64 + arm64). Each architecture's SBOM is attested separately, in both ecosystems — so one SBOM naturally appears as several signed records below. Records also accumulate as the image is rebuilt, with each release re-signing into the transparency log afresh. Every entry is independent and publicly verifiable: click any #index below to inspect it in Sigstore Rekor, or use the copy-paste commands below to verify them locally.

Build provenance slsa.dev/provenance/v1

How and where the image was built — binds this digest to the exact workflow run, commit, and builder.

signed
Verify with
Inspect Rekor log
SBOM spdx.dev/Document

Software Bill of Materials — the full inventory of packages baked into the image.

signed
Test results cosign.sigstore.dev/attestation/v1

Signed evidence that the release-gate test suite passed for this exact digest.

signed
Cosign signature sigstore.dev/cosign/sign/v1

The keyless cosign signature statement covering the image index.

signed
Verify with
Inspect Rekor log

Active Verification Toolkit

Run registry-side verification commands for the recorded release evidence.

Direct Cryptographic Evidence & Verification

Expected Certificate Subject https://github.com/northcutted/clearcutt/.github/workflows/release.yml@refs/heads/main
Expected Certificate OIDC Issuer https://token.actions.githubusercontent.com
Manifest Index Digest sha256:558cb5c5396a2dcb350cb0494abf54d718d36e08eb9adfa1af0e6efc889396e1
One-step Audit Command

Run the native compiled Go CLI command locally to verify the registry digest, Sigstore signature, SBOM and test attestations, and SLSA provenance:

clearcutt verify release-evidence \
  --ref ghcr.io/northcutted/clearcutt/clearcutt-java21@sha256:558cb5c5396a2dcb350cb0494abf54d718d36e08eb9adfa1af0e6efc889396e1 \
  --repo northcutted/clearcutt \
  --workflow-identity 'https://github.com/northcutted/clearcutt/.github/workflows/release.yml@refs/heads/main'

1. Inspect Security Metadata

Query deep, high-fidelity security metadata, dynamic entrypoints, non-root user settings, architectures, and release asset URLs.

CATALOG_DIR=./path/to/catalog
clearcutt --catalog "$CATALOG_DIR" inspect java21-slim --tag v0.12.2

2. Local Policy Gate Verification

Check catalog-record evidence flags, smoke tests, vulnerability limits, and lifecycle constraints locally or in CI pipelines. Use the release-evidence command or the Cosign/SLSA tabs for registry-side cryptographic verification.

CATALOG_DIR=./path/to/catalog
clearcutt --catalog "$CATALOG_DIR" verify image java21-slim \
  --tag v0.12.2 \
  --require-production \
  --require-signature \
  --require-sbom \
  --require-provenance \
  --max-critical 0 \
  --max-high 5

3. Runtime Conformance Audit

Verify runtime specifications offline, asserting timezone configurations, dynamic links, CA certificate paths, and rootless isolation boundaries.

clearcutt conformance run \
  --expect-runtime java

4. Scaffold Nix Overlay Graft

Under strict corporate base OS mandates, generate a workspace scaffolding to graft this runtime overlay onto existing host layers.

clearcutt overlay generate \
  --runtime java21 \
  --tier slim \
  --base registry.access.redhat.com/ubi9/ubi-minimal \
  --output my-java21-overlay/

1. Verify Keyless OIDC Signature

Confirm this OCI image was built in your official release workflow and signed via keyless OIDC certificates.

cosign verify ghcr.io/northcutted/clearcutt/clearcutt-java21@sha256:558cb5c5396a2dcb350cb0494abf54d718d36e08eb9adfa1af0e6efc889396e1 \
  --certificate-identity 'https://github.com/northcutted/clearcutt/.github/workflows/release.yml@refs/heads/main' \
  --certificate-oidc-issuer 'https://token.actions.githubusercontent.com' \
  --output json

2. Verify Cryptographic SBOM Attestation

Extract and cryptographically verify the compiled package software bill of materials statement.

cosign verify-attestation ghcr.io/northcutted/clearcutt/clearcutt-java21@sha256:558cb5c5396a2dcb350cb0494abf54d718d36e08eb9adfa1af0e6efc889396e1 \
  --type spdxjson \
  --certificate-identity 'https://github.com/northcutted/clearcutt/.github/workflows/release.yml@refs/heads/main' \
  --certificate-oidc-issuer 'https://token.actions.githubusercontent.com' \
  | jq '.payload | @base64d | fromjson | .predicate'

slsa-verifier (SLSA Build L3)

Verify SLSA Build L3 provenance from the configured builder and source ref.

slsa-verifier verify-image ghcr.io/northcutted/clearcutt/clearcutt-java21@sha256:558cb5c5396a2dcb350cb0494abf54d718d36e08eb9adfa1af0e6efc889396e1 \
  --source-uri 'github.com/northcutted/clearcutt' \
  --source-branch 'main'

GitHub Native Attestation

Audit the GitHub-native provenance attestation using the GitHub CLI client.

gh attestation verify oci://ghcr.io/northcutted/clearcutt/clearcutt-java21@sha256:558cb5c5396a2dcb350cb0494abf54d718d36e08eb9adfa1af0e6efc889396e1 \
  --repo northcutted/clearcutt \
  --cert-identity 'https://github.com/northcutted/clearcutt/.github/workflows/release.yml@refs/heads/main' \
  --source-ref refs/heads/main
Loading vulnerability data...
3

Deep-Dive & OCI Specifications

Analyze the full Nix store dependency closure, image layer architecture, and OCI configuration labels.

Software Bill of Materials

Every package included in the image's /nix/store closure. Generated from the actual OCI archive at build time and attached as an SPDX SBOM, using the same package inventory as the CVE findings above.

SBOM generated Sat, 04 Jul 2026 16:53:55 GMT. Toggle between architectures; the package set typically matches but layer hashes differ.

Loading SBOM data...
Loading layer data...

Image Specifications & Release Ledger

Inspect the static OCI container metadata labels and browse the immutable published release history for this image.

KeyValue
dev.clearcutt.recipe.license Apache-2.0
org.opencontainers.image.authors ClearCutt maintainers
org.opencontainers.image.description Hardened ClearCutt Base Image for java (21) - Tier: slim
org.opencontainers.image.licenses NOASSERTION
org.opencontainers.image.ref.name slim
org.opencontainers.image.source https://github.com/northcutted/clearcutt
org.opencontainers.image.title clearcutt-java-21
org.opencontainers.image.url https://github.com/northcutted/clearcutt
org.opencontainers.image.vendor ClearCutt
org.opencontainers.image.version 21
Tag Published Archs Packages
v0.14.0 latest Sat, 11 Jul 2026 00:47:46 GMT amd64arm64 19 .intoto.jsonl ↗
v0.13.0 Fri, 10 Jul 2026 00:21:20 GMT amd64arm64 19 .intoto.jsonl ↗
v0.12.2 Sat, 04 Jul 2026 17:29:57 GMT amd64arm64 19 .intoto.jsonl ↗
v0.12.1 Sat, 04 Jul 2026 13:08:58 GMT amd64arm64 19 .intoto.jsonl ↗
v0.11.1 Wed, 10 Jun 2026 02:52:21 GMT amd64arm64 125 .intoto.jsonl ↗
v0.11.0 Wed, 10 Jun 2026 01:24:14 GMT amd64arm64 125 .intoto.jsonl ↗
v0.10.4 Tue, 09 Jun 2026 12:54:17 GMT amd64arm64 125 .intoto.jsonl ↗
v0.10.2 Sun, 07 Jun 2026 21:31:16 GMT amd64arm64 125 .intoto.jsonl ↗
v0.10.1 Sun, 07 Jun 2026 16:42:20 GMT amd64arm64 125 .intoto.jsonl ↗
v0.10.0 Sun, 07 Jun 2026 14:37:59 GMT amd64arm64 125 .intoto.jsonl ↗