code: public void setIndices(int[] indices)
      {
          if (indices != null)
          {
              if (mIndices == null)
              {
                  setIndexBuffer(new GVRIndexBuffer(getGVRContext(), 4, indices.length));
              }
              mIndices.setIntVec(indices);
          }
          else
          {
              mIndices = null;
              NativeMesh.setIndexBuffer(getNative(), 0L);
          }
      }
docs: Sets the vertex indices of the mesh as {@code int} values.
  <p>
  If no index buffer exists, a new {@link GVRIndexBuffer} is
  constructed with {@code int} indices. Otherwise, the existing
  index buffer is updated. If that index buffer has been
  already constructed with {@code char} indices, this function
  will throw an exception.
  @param indices
  int array containing the packed index data or null.
  If null is specified, the index buffer is destroyed
  and the mesh will have only vertices.
  @see #setCharIndices(char[])
  @see #setIndexBuffer(GVRIndexBuffer)
  @see #getCharIndices()
  @see #getIndexBuffer()
  @throws IllegalArgumentException if index buffer is not <i>int</i>