Move your properties files under WEB-INF/classes. Then load it as following:
prop.load(getClass().getResourceAsStream("sample.properties"));
You can put it into sub-directory under classes as well. In this case change the call to getResourceAsStream() accordingly.
To be safer in multi-classloader system you can use Thread.getContextClassLoader().getResourceAsStream() instead.
To make the properties file to arrive to classes folder of your war file you have to put it under resources folder in your project (if you are using maven) or just under src folder if you do not use maven-like directory structure.
