A properties file is just a bunch of text lines - each containing a name and a value.
How the program interprets the value is up to the programmer. Properties files are usually read just once - when the program starts - if you want different behaviour you will have to program it.
Are you looking to replace the text DYNAMIC VALUE with a message you make up at runtime? Look at the MessageFormat doc. In recent JREs also look at PrintStream and PrintWriter printf() methods.
A good question is never answered. It is not a bolt to be tightened into place but a seed to be planted and to bear more seed toward the hope of greening the landscape of the idea. John Ciardi
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a bit of art, as a gift, the permaculture playing cards