java: convert binary string to int

Question

I\'m trying to convert a couple of binary strings back to int. However it doesn\'t convert all my binary strings, leaving me a java.lang.NumberFormatException

Answer 1

As explained above, Integer.toBinaryString() converts ~0 and ~1 to unsigned int so they will exceed Integer.MAX_VALUE.

You could use long to parse and convert back to int as below.

int base = 2;
for (Integer num : new Integer[] {~0, ~1}) {
    String binaryString = Integer.toBinaryString(num);            
    Long decimal = Long.parseLong(binaryString, base);
    System.out.println("INPUT=" + binaryString + " decimal=" + decimal.intValue()) ;
}