JTB theory
The concept of Justified True Belief implies that in order for a given proposition is true, one must believe in it to be true along with having a justification for believing it.
Gettier Case
Unlike the JTB theory, though Gettier cases contain a belief which may be considered true, it will not be considered knowledge. Read more about this case here.
After hearing strong winds pushing their bodies onto the windows along with the sound of water dripping from the leaves of the tress, I strongly believed it was raining. Nonetheless, when I went to check my window, it was only a murky weather though there was no rain present.
I had a strong belief that it was raining which was justified through the sounds I hear through the window, therefore my belief was justified. Nonetheless, when I went to check outside of the window, there was no rain present.
When I was younger, I read a book in which one of the main characters wold play a game that defined her future; if a specific happened in her present, it would define an event in the future. An example would be when she was fired from babysitting because the father kept on hitting on her thus the mother blaming her, therefore after she was fired, she sat and contemplated about what would happen next. With this, she thought, "if a red car passes, everything will be alright." Unfortunately, when a car passed, it did not have the color red. I incorporated this game into my life; whenever I would hope for something to happen, I would play this game. Sometimes, it would accidentally be true thus falling into the gettier case.
Since it was a game I would play with any situatin whatsoever, there were moments in which this game was strongly innacurate. Nonetheless, when I hoped for a red car to pass and it did, the game would turn out to be acidentally true. Because of this, this can be defined as a gettier case because though my belief wasn't justified, it still turned out to be true.