public void setThreads(int min, int max) {
    QueuedThreadPool pool = (QueuedThreadPool) webServer.getThreadPool();
    pool.setMinThreads(min);
    pool.setMaxThreads(max);
  }
Set the min, max number of worker threads (simultaneous connections).
hbase-http/src/main/java/org/apache/hadoop/hbase/http/HttpServer.java