BigInteger isProbablePrime fun with if and else loop

BigInteger is ProbablePrime() fun return a boolean value. if use if else condition then some test cases pass some wrong. like code is

BigInteger b=new BigInteger(n);

if(b.isProbablePrime(1)) {
    System.out.println("prime");
} else {
    System.out.println("Not prime");
}

else if use like code use a ternary expression then all test case has done

System.out.println(b.isProbablePrime(1) ? "prime" : "not prime");

I don't understand this thing so please help me.