When you want to connect to a WMS server and visualize data, you need to know which data sets are available.

First, you need to create a TLcdWMSClient instance: 

String serverURL = "https://sampleservices.luciad.com/wms";
TLcdWMSClient wmsClient = TLcdWMSClient.createWMSClient(new URI(serverURL));

The client offers API to perform a GetCapabilities request: 

ALcdOGCWMSCapabilities capabilities = wmsClient.getCachedCapabilities();

The return value is a Java object representing the capabilities exposed by the server.

If we now loop over the capabilities, we can collect all available WMS layers:

List<String> allAvailableLayerNames = new ArrayList<>();
//On a WMS server, the layers are stored in a hierarchy
//Loop over the hierarchy to collect them all
for (int i = 0; i < capabilities.getWMSRootNamedLayerCount(); i++) {
  ALcdWMSNamedLayer rootNamedLayer = capabilities.getWMSRootNamedLayer(i);
  allAvailableLayerNames.addAll(getAvailableLayerNames(rootNamedLayer));
}

Because a WMS server stores the layers in a hierarchical structure, we use recursion to implement the getAvailableLayerNames method: 

private static List<String> getAvailableLayerNames(ALcdWMSNamedLayer aWMSNamedLayer) {
  List<String> result = new ArrayList<>();
  //Add the current layer
  String layerName = aWMSNamedLayer.getNamedLayerName();
  if (layerName != null) {
    result.add(layerName);
  }

  //Use recursion to add all the child layers
  for (int i = 0; i < aWMSNamedLayer.getChildWMSNamedLayerCount(); i++) {
    result.addAll(getAvailableLayerNames(aWMSNamedLayer.getChildWMSNamedLayer(i)));
  }
  return result;
}

Find below a runnable example which lists the available data sets on our sample server:

import java.net.URI;
import java.util.ArrayList;
import java.util.List;

import com.luciad.wms.client.model.ALcdOGCWMSCapabilities;
import com.luciad.wms.client.model.ALcdWMSNamedLayer;
import com.luciad.wms.client.model.TLcdWMSClient;

class FindAvailableDataTutorial {

  public static void main(String[] args) throws Exception {
    String serverURL = "https://sampleservices.luciad.com/wms";
    TLcdWMSClient wmsClient = TLcdWMSClient.createWMSClient(new URI(serverURL));

    ALcdOGCWMSCapabilities capabilities = wmsClient.getCachedCapabilities();

    List<String> allAvailableLayerNames = new ArrayList<>();
    //On a WMS server, the layers are stored in a hierarchy
    //Loop over the hierarchy to collect them all
    for (int i = 0; i < capabilities.getWMSRootNamedLayerCount(); i++) {
      ALcdWMSNamedLayer rootNamedLayer = capabilities.getWMSRootNamedLayer(i);
      allAvailableLayerNames.addAll(getAvailableLayerNames(rootNamedLayer));
    }

    System.out.println("Available WMS layers on " + serverURL + ": \n");
    allAvailableLayerNames.stream()
                          .sorted()
                          .forEach(System.out::println);
  }

  private static List<String> getAvailableLayerNames(ALcdWMSNamedLayer aWMSNamedLayer) {
    List<String> result = new ArrayList<>();
    //Add the current layer
    String layerName = aWMSNamedLayer.getNamedLayerName();
    if (layerName != null) {
      result.add(layerName);
    }

    //Use recursion to add all the child layers
    for (int i = 0; i < aWMSNamedLayer.getChildWMSNamedLayerCount(); i++) {
      result.addAll(getAvailableLayerNames(aWMSNamedLayer.getChildWMSNamedLayer(i)));
    }
    return result;
  }
}