ArcObjects(Java) - register table to geodatabase ESRI 10.3

There are a couple of ways to connect to the geodatabase and targeting a specific schema using the SDEWorkspaceFactory class. One can build up a PropertySet of the connection properties or provide a path to an existing SDE connection file using the desired credentials. Both of these methods are described in the link provided by Vince above.

SdeWorkspaceFactory workspaceFactory = new SdeWorkspaceFactory();
IWorkspace workspace = workspaceFactory.openFromFile("C:Pathtoconnection_file.sde", 0);

SdeWorkspaceFactory: http://desktop.arcgis.com/en/arcobjects/latest/java/api/arcobjects/com/esri/arcgis/datasourcesGDB/SdeWorkspaceFactory.html

To register spatial tables as feature classes in a geodatabase, one could use the Geoprocessing package and fire off the Register With Geodatabase geoprocessing tool.

String inputConnString = "C:\Tempconn_to_gdb.sde";
String fcName = "MySpatialTable";
String featureClassPath = inputConnString + "\" + fcName;

ISpatialReferenceFactory srFactory = new SpatialReferenceEnvironment();
ISpatialReference srs = srFactory.createGeographicCoordinateSystem(wkid);

GeoProcessor geoProcessor = new GeoProcessor();

    VarArray parameters = new VarArray();
    parameters.add(featureClassPath);
    parameters.add("OBJECTID");
    parameters.add("Shape");
    parameters.add("POINT");
    parameters.add(srs);

geoProcessor.execute("RegisterWithGeodatabase_management", parameters, null);

List of Java ArcObject Geoprocessing Data Management tools: http://desktop.arcgis.com/en/arcobjects/latest/java/api/arcobjects/com/esri/arcgis/geoprocessing/tools/datamanagementtools/package-frame.html

Class RegisterWithGeodatabase http://desktop.arcgis.com/en/arcobjects/latest/java/api/arcobjects/com/esri/arcgis/geoprocessing/tools/datamanagementtools/RegisterWithGeodatabase.html

ArcPy RegisterWithGeodatabase_Management http://desktop.arcgis.com/en/arcmap/latest/tools/data-management-toolbox/register-with-geodatabase.htm