@Test
  public void testCoprocessorConfigurationOnlineChangeOnMaster() {
    assertNull(hMaster.getMasterCoprocessorHost().findCoprocessor(JMXListener.class.getName()));
    conf.set(CoprocessorHost.MASTER_COPROCESSOR_CONF_KEY, JMXListener.class.getName());
    assertFalse(hMaster.isInMaintenanceMode());
    hMaster.getConfigurationManager().notifyAllObservers(conf);
    assertNotNull(hMaster.getMasterCoprocessorHost().findCoprocessor(JMXListener.class.getName()));
  }
Test that the configurations in the CompactionConfiguration class change properly.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestRegionServerOnlineConfigChange.java