Using Gdal warp on shapefiles with GDAL Java Bindings

Question

I am trying to write a method in Java that transforms from one CRS to another using GDAL's Java Bindings. Specifically from 3857 to 4326 (and a few others will be common to my use cases).

Here is my code so far (one easy to read permutation of the hundreds of things I've tried). The source and dest strings are paths to shapefiles

public static void warp(String source, String dest) {
    ogr.RegisterAll();
    Vector<String> options = new Vector<>();
    options.add("-s_srs");
    options.add("3857");
    options.add("-t_srs");
    options.add("4326");

    WarpOptions ops = new WarpOptions(options);
    Dataset[] des = new Dataset[1];
    des[0]=gdal.Open(dest);
 
    Dataset src = gdal.OpenEx(source);
    int Warp = gdal.Warp(src, des, ops);

  }

This is all I get for an error/exception:

ERROR 1: Translating source or target SRS failed: 3857