geopackage-sdk/src/main/java/mil/nga/geopackage/factory/GeoPackageManagerImpl.java
private void addExternalDatabases(Collection<String> databases) {
        // Get the external GeoPackages, adding those where the file exists and
        // deleting those with missing files
        List<GeoPackageMetadata> externalGeoPackages = getExternalGeoPackages();
        for (GeoPackageMetadata external : externalGeoPackages) {
            if (new File(external.getExternalPath()).exists()) {
                databases.add(external.getName());
            } else {
                delete(external.getName());
            }
        }
    }
private void addExternalDatabases(Collection<String> databases) {
        // Get the external GeoPackages, adding those where the file exists and
        // deleting those with missing files
        List<GeoPackageMetadata> externalGeoPackages = getExternalGeoPackages();
        for (GeoPackageMetadata external : externalGeoPackages) {
            if (new File(external.getExternalPath()).exists()) {
                databases.add(external.getName());
            } else {
                delete(external.getName());
            }
        }
    }
Add all external databases to the collection

@param databases