First you need to understand the mathematics behind it. Any number (that is a whole number, without a fraction part like for example 1.5) will give the reminder 0 when divided by one:
n % 1 == 0
This condition will therefore always be true.
If your case, once you are at n = 1, you return false.
I suggest you print out the output at every line of your program, and you will see the behavior.
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solved issue in loop of finding prime number in java [closed]