graphdb/src/main/java/com/tinkerpop/blueprints/impls/orient/OrientBaseGraph.java
public void dropVertexType(final String iTypeName) {
    makeActive();

    if (getDatabase().countClass(iTypeName) > 0)
      throw new OCommandExecutionException("cannot drop vertex type '" + iTypeName
          + "' because it contains Vertices. Use 'DELETE VERTEX' command first to remove data");

    executeOutsideTx(new OCallable<OClass, OrientBaseGraph>() {
      @Override
      public OClass call(final OrientBaseGraph g) {
        ODatabaseDocument rawGraph = getRawGraph();
        rawGraph.getMetadata().getSchema().dropClass(iTypeName);
        return null;
      }
    }, "drop vertex type '", iTypeName, "'");
  }
public void dropVertexType(final String iTypeName) {
    makeActive();

    if (getDatabase().countClass(iTypeName) > 0)
      throw new OCommandExecutionException("cannot drop vertex type '" + iTypeName
          + "' because it contains Vertices. Use 'DELETE VERTEX' command first to remove data");

    executeOutsideTx(new OCallable<OClass, OrientBaseGraph>() {
      @Override
      public OClass call(final OrientBaseGraph g) {
        ODatabaseDocument rawGraph = getRawGraph();
        rawGraph.getMetadata().getSchema().dropClass(iTypeName);
        return null;
      }
    }, "drop vertex type '", iTypeName, "'");
  }
Drop a vertex class.

@param iTypeName Vertex class name