output: #fixed code
                                  protected static String rootPath() {
          String path = OS.getTarget();
          String sep = System.getProperty("file.separator");
  
          if (!path.endsWith(sep)) {
              path += sep;
          }
  
          return path + "chronicle-jul" + Time.uniqueId();
      }
input: #vulnerable code 
                                  protected static String rootPath() {
          String path = System.getProperty("java.io.tmpdir");
          String sep = System.getProperty("file.separator");
  
          if (!path.endsWith(sep)) {
              path += sep;
          }
  
          return path + "chronicle-jul";
      } 
                              #location 5 
                              #vulnerability type NULL_DEREFERENCE