Quark.jar

java -jar quark.jar squash --config quark.properties --input app.jar --output app_optimized.jar Keep META-INF/services/* if you use ServiceLoader ; otherwise, your service providers will disappear. Common Pitfalls and Troubleshooting Even a sharp tool can cut the wrong way. Here is what to watch for. Problem 1: "Unsupported class file version" Error: java.lang.IllegalArgumentException: Unsupported version 65.0

quark.jar cannot statically determine which methods are called via Class.getMethod() . quark.jar

quark.jar does not rename classes or fields by default, meaning your reflection code won't break—a common pain point with ProGuard. Downloading and Verifying quark.jar Before execution, ensure you have the legitimate artifact. The official distribution point is the Quark Project GitHub repository (not Maven Central, as of the latest release). Step 1: Download wget https://github.com/quark-project/quark/releases/download/v2.1.0/quark.jar Step 2: Verify Checksum (Security) sha256sum quark.jar # Expected output: 8a7e4b9f2c3d1e5a6b7c8d9e0f1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0 Always check the official release page for the current hash. Step 3: Test Execution java -jar quark.jar --version If you see Quark Bytecode Tool v2.1.0 , you are ready. Core Commands and Practical Examples The power of quark.jar lies in its subcommands. Let's explore the three most important ones. 1. Analyzing a JAR File (The info command) Before optimizing, understand what you are dealing with. java -jar quark