Overview

This program will find the Maven coordinates for all the Java archive (e.g., jar) files in a specified directory.

Rationale

I inherited a Java program that was packaged using a custom build utility. I wanted to move it over to Maven or Gradle, so I could automate the build using a tool like Jenkins or Travis CI.

This program had over 200 libraries it used, and I did not want to search Maven Central manually for all of these libraries.

That's when I found make-pom. While I really loved make-pom, I ran into some challenges getting it set up on my laptop. That, and I didn't like the fact that it required Bourne shell, Python 2, and a few other external binaries like sha1sum.

I decided to write a program that did much the same thing, but entirely in Java. I also introduced caching, external configuration, logging, output options, and multiple Maven repository searching.

Algorithm

1. Look for each Java archive (e.g., .jar) file in a specified directory.
2. Calculate the hash value for the given file.
3. Determine if we already have the Maven coordinates for this file.
4. If not, see if the file includes a pom.properties file.
5. If not, search Maven Central for the given hash value.
6. Store the Maven coordinates in an internal database for future reference.
7. Output the Maven coordinates as requested (e.g., POM, JSON, not at all).

Configuration

See find-dependency.json. This program will look for this file in the class path.

Usage

$ java -jar find-dependency-1.0.jar -d /path/to/archives [-o fn [-f fmt]]

Command Line Options

Option	Description	Default
-d dir, --directory dir	The directory to look for Java archive files.	None. This option is required.
-f fmt, --format fmt	The output file format. One of JSON or POM. Only valid when used with -o or --output.	JSON
-o fn, --output fn	The output file.	None. If not specified, nothing is output, just loaded in the database.

Dependencies

This program makes use of features that require Java 11 or newer (e.g., HTTP Client).

This program also makes use of the following external libraries:

• Apache Commons CLI
• Apache Log4j2
• Google Guava
• Google Gson
• H2 Database

Backend Database

This program uses H2 as a database to cache results. You can easily use a different database by changing the driver, connection string, and SQL statements in find-dependency.json.

Future Enhancements

1. Better results handling when searching multiple Maven repositories.

Credits

This program was heavily-inspired by make-pom. Thanks, @sjbotha!