code: public static File getLogDir() {
  
          String logDirLoc = null;
  
          // 1st check in environment variable is set.  This is the normal case
          // when the server is started from the command line.
          if (logDir.get() == null) {
              File resultDir = null;
              try {
                  logDirLoc = AccessController.doPrivileged(new java.security.PrivilegedExceptionAction<String>() {
                      @Override
                      public String run() throws Exception {
                          return System.getenv(BootstrapConstants.ENV_LOG_DIR);
                      }
                  });
              } catch (Exception ex) {
              }
  
              //outputDirLoc = System.getenv(BootstrapConstants.ENV_WLP_OUTPUT_DIR);
              if (logDirLoc != null) {
                  resultDir = new File(logDirLoc);
              } else {
                  // PI20344: Check if the Java property is set, which is the normal case when
                  // the server is embedded; i.e. they didn't launch it from the command line.
                  logDirLoc = System.getProperty(BootstrapConstants.ENV_LOG_DIR);
                  if (logDirLoc != null) {
                      resultDir = new File(logDirLoc);
                  }
              }
              logDir = StaticValue.mutateStaticValue(logDir, new FileInitializer(resultDir));
          }
  
          return logDir.get();
      }
docs: Returns directory containing server log directories.
  
  @return instance of the log directory or 'null' if LOG_DIR is not defined