output: #fixed code
                                  public void createClient() {
          // Create objects Enabler
          ObjectsInitializer initializer = new ObjectsInitializer(new LwM2mModel(createObjectModels()));
          initializer.setInstancesForObject(LwM2mId.SECURITY, Security.noSec(
                  "coap://" + server.getUnsecuredAddress().getHostString() + ":" + server.getUnsecuredAddress().getPort(),
                  12345));
          initializer.setInstancesForObject(LwM2mId.SERVER, new Server(12345, LIFETIME, BindingMode.U, false));
          initializer.setInstancesForObject(LwM2mId.DEVICE, new Device("Eclipse Leshan", MODEL_NUMBER, "12345", "U") {
              @Override
              public ExecuteResponse execute(int resourceid, String params) {
                  if (resourceid == 4) {
                      return ExecuteResponse.success();
                  } else {
                      return super.execute(resourceid, params);
                  }
              }
          });
          List<LwM2mObjectEnabler> objects = initializer.createMandatory();
          objects.addAll(initializer.create(2, 2000));
  
          // Build Client
          LeshanClientBuilder builder = new LeshanClientBuilder(currentEndpointIdentifier.get());
          builder.setObjects(objects);
          client = builder.build();
      }
input: #vulnerable code 
                                  public void createClient() {
          // Create objects Enabler
          ObjectsInitializer initializer = new ObjectsInitializer(new LwM2mModel(createObjectModels()));
          initializer.setInstancesForObject(LwM2mId.SECURITY, Security.noSec(
                  "coap://" + server.getNonSecureAddress().getHostString() + ":" + server.getNonSecureAddress().getPort(),
                  12345));
          initializer.setInstancesForObject(LwM2mId.SERVER, new Server(12345, LIFETIME, BindingMode.U, false));
          initializer.setInstancesForObject(LwM2mId.DEVICE, new Device("Eclipse Leshan", MODEL_NUMBER, "12345", "U") {
              @Override
              public ExecuteResponse execute(int resourceid, String params) {
                  if (resourceid == 4) {
                      return ExecuteResponse.success();
                  } else {
                      return super.execute(resourceid, params);
                  }
              }
          });
          List<LwM2mObjectEnabler> objects = initializer.createMandatory();
          objects.addAll(initializer.create(2, 2000));
  
          // Build Client
          LeshanClientBuilder builder = new LeshanClientBuilder(currentEndpointIdentifier.get());
          builder.setObjects(objects);
          client = builder.build();
      } 
                              #location 5 
                              #vulnerability type NULL_DEREFERENCE