Java - How To Reject Binary Values Longer Than 32 Bits (User Input)

I am designing a program in-order convert Binary to Decimal values with added features:

Rejecting binary values longer than 32 bits

Prompting the user to make multiple entries after completing the binary to decimal conversion of their first entry. I was trying to code this in Nested For Loops, but I don't know if I've really done that.

Here is what i have so far.

public class BinaryToDecimal {
public static void main(String[] args){
Scanner scan = new Scanner(System.in);
String binary;
int decimal=0b10, i, rem;
boolean isBinary = true;
 
[Code] ....