### Read Heroes

We can **read** `Hero`s from the database using a `select()`. We can include a `limit` and `offset` to paginate the results.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[48:55] hl[51:52,54] *}

### Read One Hero

We can **read** a single `Hero`.

        }
    }

    static class Sem {
        Sem( int count ) {
            this.count = count;
        }
        int count;
    }

    static class QueryThread extends Thread {
    
        Sem sem;
        String host, scope;
        int type;
        NbtAddress ans = null;
        InetAddress svr;
        UnknownHostException uhe;
    

    int countToRemove = 30;
    AtomicInteger current = new AtomicInteger(countToRemove);

    when(backingMap.get(KEY)).thenReturn(current);
    // it's ok if removal fails: another thread may have done the remove
    when(backingMap.remove(KEY, current)).thenReturn(false);

    assertEquals(countToRemove, multiset.remove(KEY, countToRemove));
    assertEquals(0, current.get());
  }

   * </ul>
   *
   * <p>The overall principle is to continue to treat every checked exception as a checked
   * exception, every unchecked exception as an unchecked exception, and every error as an error. In
   * addition, the cause of any {@code ExecutionException} is wrapped in order to ensure that the
   * new stack trace matches that of the current thread.
   *

    public static final String INCREMENTAL_CRAWLING_PROPERTY = "crawling.incremental";

    public static final String CRAWLING_THREAD_COUNT_PROPERTY = "crawling.thread.count";

    public static final String CRAWLING_USER_AGENT_PROPERTY = "crawling.user.agent";

    public static final String DAY_FOR_CLEANUP_PROPERTY = "day.for.cleanup";

        return xPathApi.evaluateExpression(xpath, doc, XPathNodes.class);
    }

    protected XPathAPI getXPathAPI() {
        try {
            return xpathAPICache.get(Thread.currentThread().getName());
        } catch (final ExecutionException e) {
            if (logger.isDebugEnabled()) {
                logger.debug("Failed to retrieval a cache.", e);
            }

   * values.
   *
   * <p>Elements are copied from the argument collection as if by {@code collection.toArray()}.
   * Calling this method is as thread-safe as calling that method.
   *
   * <p><b>Note:</b> consider representing the collection as a {@link java.util.BitSet} instead.
   *
   * @param collection a collection of {@code Boolean} objects

   * values.
   *
   * <p>Elements are copied from the argument collection as if by {@code collection.toArray()}.
   * Calling this method is as thread-safe as calling that method.
   *
   * <p><b>Note:</b> consider representing the collection as a {@link java.util.BitSet} instead.
   *
   * @param collection a collection of {@code Boolean} objects

   * allow in normal conditions. This is enforced by "throttling" incoming requests as needed. For
   * example, we could compute the appropriate throttle time for an incoming request, and make the
   * calling thread wait for that time.
   *
   * The simplest way to maintain a rate of QPS is to keep the timestamp of the last granted
   * request, and ensure that (1/QPS) seconds have elapsed since then. For example, for a rate of

    }

    public void execute() {
      RunnableExecutorPair stack;
      do {
        stack = head;
        if (stack == null) {
          // If head == null then execute() has been called so we should just return
          return;
        }
        // try to swap null into head.
      } while (!UNSAFE.compareAndSwapObject(this, HEAD_OFFSET, stack, null));

      RunnableExecutorPair reversedStack = null;