javaexceptiontype-conversionradixnumberformatexception

NumberFormatExcpetion while using Long.parseLong() to parse a base-2 number(as a string) to a base-10 Long int

So I'm trying to flip the bits of a long int, this is how I'm doing it but I'm getting the NumberFormatException. I'm converting it to a base-2 string and add zeros to the left to become a 32 char, then flip the bits, then convert it back to long of base-10.

Long n =4L;
String bits = String.format("%32s", Long.toBinaryString(n)).replace(' ', '0');
bits = bits.replace("0", "3");
bits = bits.replace("1", "0");
bits = bits.replace("3", "1");
return Long.parseLong(bits.trim(), 10);

4L after converting to base 2:

00000000000000000000000000000100

after flipping all bits:, I'm getting this:

Exception in thread "main" java.lang.NumberFormatException: For input string: "11111111111111111111111111111011"

What's wrong? I checked for non-printable chars but there aren't, also I trimmed the number in case there are any extra spaces, I tried to add L at the end but nothing worked, what's the problem?

Solution

  • So the problem was with the radix parameter of the parseLong method, radix is to specify the base of the string that I want to parse, not the output of the parse method

    So the whole issue was solved by substituting this:

    return Long.parseLong(bits.trim(), 10);

    with this:

    return Long.parseLong(bits.trim(), 2);

    now, the string of bits (the input of parseLong method) is of base 2 as mentioned in the radix parameter