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jfind

A cross-platform command-line tool to find and evaluate Java installations on your system. It can locate Java executables and optionally evaluate their version information, providing output in both text and JSON formats.

Features

  • Find Java executables recursively in specified directories
  • Detect Oracle JDKs (prints warning in text mode, sets is_oracle flag in JSON mode)
  • Cross-platform support (Windows, Linux, macOS)
  • Optional evaluation of Java version information
  • JSON output format with metadata (including platform information)
  • Configurable search depth
  • License requirement detection for Java runtimes
  • Display license check rules

License Requirement Detection

When using the -eval flag, jfind determines if a Java runtime requires a commercial license based on the following rules:

  1. OpenJDK: Never requires a license

    • Any runtime containing "openjdk" in its name (case-insensitive)
    • Specifically "OpenJDK Runtime Environment"

  2. Commercial Features: Requires a license if

    • Runtime description contains "commercial" (case-insensitive)

  3. Oracle JDK Version Rules:

    • JDK 7: Requires license for updates > 80
    • JDK 8: Requires license for updates > 202
    • JDK 11: Always requires license
    • JDK 17: Requires license for versions 17.0.13 and later
    • JDK 18-20: No license required
    • JDK 21+: No license required
    • Other versions: License required by default

Use the -require-license flag to filter and show only Java installations that require a commercial license.

Installation

Building from Source

  1. Ensure you have Go installed on your system
  2. Clone the repository
  3. Build using task:
task build        # Build for current platform
task build:all    # Build for all supported platforms

Usage

Basic usage:

jfind -path <search_path> [options]

Options

  • -path string: Starting path for search (required)
  • -depth int: Maximum depth to search (-1 for unlimited)
  • -eval: Evaluate found java executables
  • -json: Output results in JSON format
  • -post: Post JSON output to server (implies --json)
  • -url string: URL to post JSON output to (only used with --post, default http://localhost:8000/api/jfind)
  • -require-license: Filter only Java runtimes that require a commercial license (requires --eval)
  • -show-rules: Display license check rules and exit
  • -h, -help: Show help message

Note: All options can be specified with either single dash (-) or double dash (--).

Examples

Find Java installations in /usr/lib/jvm:

jfind -path /usr/lib/jvm

Find and evaluate Java installations with JSON output:

jfind -path /usr/lib/jvm -eval -json

Find Java installations requiring commercial license:

jfind -path /opt -eval -require-license

Find Java installations requiring license and post results to server:

jfind -path /usr/local -eval -require-license -post

Display license check rules:

jfind -show-rules

Output Formats

Text Output (default)

Java executable: /path/to/java
Java version: 11.0.12
Java vendor: Oracle Corporation
Java runtime name: Java(TM) SE Runtime Environment

JSON Output

When using the -json flag, output will be in JSON format:

{
  "meta": {
    "scan_ts": "2025-02-04T15:12:01Z",      // Scan timestamp in UTC
    "computer_name": "hostname",             // Name of the computer
    "user_name": "username",                 // Name of the user
    "scan_duration": "PT5S",                 // Scan duration in ISO 8601
    "has_oracle_jdk": true,                  // Whether any Oracle JDK was found
    "count_result": 3,                       // Total number of Java executables found
    "count_require_license": 1,              // Number requiring commercial license
    "scanned_dirs": 150,                     // Number of directories scanned
    "scan_path": "/usr/lib/jvm"             // Starting path for scan
  },
  "result": [
    {
      "java_executable": "/path/to/java",    // Path to Java executable
      "java_runtime": "OpenJDK Runtime Environment", // Runtime name if evaluated
      "java_vendor": "Eclipse Adoptium",     // Vendor if evaluated
      "is_oracle": false,                    // Whether it's an Oracle JDK/JRE
      "java_version": "17.0.8.1",           // Version if evaluated
      "java_version_major": 17,             // Major version if evaluated
      "java_version_update": 8,             // Update version if evaluated
      "exec_failed": false,                 // True if evaluation failed
      "require_license": false              // Whether commercial license is required
    }
  ]
}

When using -post, this JSON will be sent to the specified server URL. The server will respond with:

{
  "result": "ok",
  "scan_id": "<unique_scan_id>"
}