code: public String debugInfo() {
          if (!isDebug || debugEntries.size() == 0) {
              return "";
          }
          StringBuffer ret = new StringBuffer();
          for (int i = debugEntries.size() - 1;i >= 0;i--) {
              Entry entry = debugEntries.get(i);
              ret.append(entry.timestamp).append(": ").append(entry.message).append("\n");
              if (entry.throwable != null) {
                  StringWriter writer = new StringWriter();
                  entry.throwable.printStackTrace(new PrintWriter(writer));
                  ret.append(writer.toString());
              }
          }
          return ret.toString();
      }
docs: Get back all previously logged and stored debug messages
  
  @return debug string