IntelliJ console sometimes not displaying output

public class Output {
    protected static void secondGen(String[][] arr,int N,int M){
        String[][] arrSwap = new String[N][M];
        int count=0;
        for(int i=0;i<N;i++){
            for(int j = 0; j<M;j++){
                count++;
                int random = ThreadLocalRandom.current().nextInt(1,((N*M)/2)+1);
                String number = String.valueOf(random);
                arrSwap[i][j] = number;
                if(count%2==0){
                    if(!ArrayGen.arrOutputValidation(arrSwap,N,M,i,j)){
                        j--;
                        count--;
                    }
                }
            }
        }
        Utility.render(arrSwap);
    }
}

Sometimes at random console just hangs up and doesn't show any output. In those instances I can just continue typing lines forever in the console even though I shouldn't be able to type anything more and nothing ever comes up. While other times the Utillity.render(Which is essentially a customized System.out.println) renders the array and the program finishes.

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