code: public String getLogProviderDefinition(BootstrapConfig bootProps) {
          String logProvider = bootProps.get(BOOTPROP_LOG_PROVIDER);
  
          if (logProvider == null)
              logProvider = defaults.getProperty(MANIFEST_LOG_PROVIDER);
  
          if (logProvider != null)
              bootProps.put(BOOTPROP_LOG_PROVIDER, logProvider);
  
          return logProvider;
      }
docs: Find and return the name of the log provider. Look in
  bootstrap properties first, if not explicitly defined there, get
  the default from the manifest.
  
  @return the selected log provider