public static void setRootLevel(String levelName) {
    Method method = getMethod("setRootLevel", String.class);
    invoke(method, levelName);
  }
A bridge class for operating on log4j, such as changing log level, etc.
<p/>
Will call the methods in {@link InternalLog4jUtils} to actually operate on the log4j stuff.
hbase-logging/src/main/java/org/apache/hadoop/hbase/logging/Log4jUtils.java