gistfile1.txt

 r.db(dbName).table(tableName).filter(new DBLambda() {
                  @Override
                  public RTFluentRow apply(RTFluentRow row) {
                      return row.or(
                          row.and(
                                  row.field("age").gt(20),
                                  row.field("age").lt(30)
                          ),
                          row.field("name").eq("heman")
                      );
                  }
              }).run(con).size()
              
              
// Java 8

   r.db(dbName).table(tableName).filter(row -> row.or(
                            row.and(
                                    row.field("age").gt(20),
                                    row.field("age").lt(30)
                            ),
                            row.field("name").eq("heman")
  )).run(con).size()