Vending machine pro in validation I want to throw customized exception and call the method again to make payment successfully

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Java

if(sum<total) {
int temp5=total-sum;
throw new InsufficientFund("Incomplete Transaction
Please pay remaining amount: " +temp5);

}
else if(sum==total) {
throw new TransactionComplete("Transaction Complete
Thank You for using Machine");
}
else if(sum>total) {
int temp5=total-sum;
throw new ExtraAmountPaid("Extra Amount Paid please
take remainging amount: " +temp5);
}

What I have tried:

Tried using this keywoods also loops but didn't find solution