When to use "getResourceAsStream" method?

I was confused using the said method because while loading some properties file people are following a different approaches...

Properties prop 
  = new Properties(new FileInputStream(new File("<path of the properties file>"));
 

and few are using..

Properties prop 
  = new Properties(getClass().getResourceAsStream("<path of the properties file>"));
 

Which one to use when?

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