Technic Launcher

Technic Launcher is a desktop application built specifically for use with the Technic Platform, letting players discover, install, update, and play Minecraft modpacks. This repository (LauncherV3) contains the Java launcher, its Technic Platform and Solder integrations, and platform packaging tools.

• Solder Java runtime overrides — select a Mojang Java runtime for a Solder build, including validation and manual-Java behavior.
• Local Solder integration testing — connect a local Solder instance through the Platform fixture and test with an isolated launcher profile.
• Modern Forge and NeoForge installation — installer processing, shared libraries, cache migration, offline limitations, and corpus verification.

See the changelog for recent changes and history for older releases.

Use the included Gradle wrapper from the repository root. The build uses a Java 25 toolchain with automatic toolchain provisioning configured; production sources target Java 8. The Java runtime needed by a Minecraft modpack is selected separately from the build toolchain.

On Windows, use gradlew.bat in place of ./gradlew.

For local testing, set BUILD_NUMBER=999 so communication with the Technic Platform API works. On Windows, set this environment variable before invoking gradlew.bat.

# Run the launcher (requires a graphical desktop)
BUILD_NUMBER=999 ./gradlew run

# Build the standalone JAR
BUILD_NUMBER=999 ./gradlew shadowJar

The example produces build/libs/launcher-4.0-999.jar. Without BUILD_NUMBER, the build defaults to 0; use 999 for local testing. For local Solder testing without using your normal launcher profile, follow the isolated-profile guide.

Signing during package is enabled when CERT_KEYSTORE is set and also requires CERT_ALIAS, CERT_STOREPASS, and CERT_KEYPASS. Setting SENTRY_AUTH_TOKEN enables Sentry source bundle upload. Keep credentials and generated files out of version control.

# Open the real dialog with a simulated 4 GiB heap and 2 GiB available.
./gradlew previewMemoryWarning

# Supply a different simulated heap and available memory, both in MiB.
./gradlew previewMemoryWarning --args="8192 4096"

# Healthy and unknown readings should finish without displaying a warning.
./gradlew previewMemoryWarning --args="4096 8192"
./gradlew previewMemoryWarning --args="4096 -1"

The preview reports Cancel or Launch anyway in the terminal. It does not generate memory pressure, load or save launcher settings, or start Minecraft. It uses the production warning dialog; the preview script itself is development-only and is not included in the launcher JAR.

./gradlew test --tests net.technicpack.utilslib.OSUtilsTest

These tests expose synthetic macOS-style functions through JNA and exercise the native calling interface, ARM64/Intel results, and unavailable or malformed query results. They run locally without a Mac or C compiler. They do not verify Apple's actual sysctl implementation or Rosetta; that still requires an Apple Silicon Mac, such as a suitable hosted macOS runner.

Launcher-process HTTPS uses only the Mozilla roots in src/main/resources/tls/cacert.pem, filtered by the bundled Mozilla OneCRL snapshot in onecrl.json. Both URLConnection (including Sentry) and the Google HTTP authentication clients use this policy. Authentication uses the JDK-backed NetHttpTransport to support older Java 8 runtimes. The policy is installed before services start; invalid or missing TLS inputs stop startup rather than falling back to Java's trust store. Private/company CAs installed only in Java or OS trust stores, including a store selected through javax.net.ssl.trustStore, are intentionally not trusted.

Before each release, explicitly refresh and review all three versioned inputs:

python3 scripts/refresh-tls-data.py
python3 scripts/refresh-tls-data.py --check
python3 -B scripts/test_refresh_tls_data.py
BUILD_NUMBER=0 ./gradlew check shadowJar

The standard-library-only Python utility downloads over verified HTTPS, verifies curl's published PEM SHA-256, validates OneCRL records and pagination, and stages files only after validation succeeds. --check works offline and never modifies the files. Ordinary builds use the versioned snapshot; Gradle does not download trust data. sources.json records UTC retrieval time, source URLs, the collection ETag, counts and hashes of the exact shipped bytes. These checks/provenance do not constitute independent cryptographic authentication. A refresh interrupted during file replacement must not be released: rerun --check and complete a successful refresh.

Release verification must execute the packaged policy on legacy Java 8u202 and Java 25. CI runs this smoke before uploading artifacts, using a checksum-pinned 8u202 runtime. A current Java 8 update alone is insufficient: it contains APIs absent from older installations. This legacy runtime is only an offline compatibility-test fixture, not a recommended runtime or a new minimum Java requirement. With JAVA25_HOME and JAVA8_HOME pointing to Java 25 and 8u202:

"$JAVA25_HOME/bin/javac" --release 8 -cp build/libs/launcher-4.0-0.jar \
  -d build/tls-smoke \
  src/test/java/net/technicpack/utilslib/TlsTestFixture.java \
  src/test/java/net/technicpack/utilslib/TlsSmoke.java
"$JAVA8_HOME/bin/java" \
  -cp build/tls-smoke:src/test/resources:build/libs/launcher-4.0-0.jar \
  net.technicpack.utilslib.TlsSmoke
"$JAVA25_HOME/bin/java" \
  -cp build/tls-smoke:src/test/resources:build/libs/launcher-4.0-0.jar \
  net.technicpack.utilslib.TlsSmoke

Use ; instead of : as the classpath separator on Windows. The smoke uses loopback HTTPS, loads production classes/data from the shadow JAR, checks both transports and startup failure, and exits nonzero on failure. A --release 8 compile alone is not Java 8 runtime proof. If DISPLAY points at a nonexistent X server in a headless environment, unset it for Gradle tests.

The test-only TLS fixtures use RSA-2048/SHA-256, normal validity from 2020-01-01 to 2120-01-01 and an expired leaf valid from 2000-01-01 to 2001-01-01. Only the test server's leaf private key is stored; CA private keys were not retained. Twelve public eMudhra TLS certificates from Mozilla bug 2083449 are regression evidence, not trust anchors; source attachment IDs and certificate fingerprints are recorded in TlsTestFixture.java. Tests must continue to reject every one against the current bundled feed: missing coverage is a security-data release blocker, not a reason to remove a fixture. Neither these certificates nor the test server key belong in the shipped JAR.

The snapshot remains enforced indefinitely; it is neither refreshed nor disabled based on age at runtime. Newly discovered revocations require a launcher update. This protects against the bundled known revocations, not all website/leaf revocations. It does not import all Firefox trust-policy constraints (curl export limitations), repair other old-Java vulnerabilities, or change the separate Minecraft JVM's TLS configuration.

• src/main/java/net/technicpack/ — launcher UI, installation and update flows, and shared utilities.
• src/main/resources/ — bundled images, translations, metadata, and Windows packaging assets.
• src/main/app/ — macOS application assets.
• src/test/java/ — tests mirroring production packages.
• buildSrc/src/main/kotlin/ — custom Gradle build and packaging logic.
• scripts/ — development utilities, including the local Platform fixture.
• docs/ — detailed guides and existing design documents.

The launcher is licensed under the GNU General Public License, version 3 or later. See LICENSE.txt and COPYING.txt for the Technic Launcher Core license notice and bundled license text.