Convert decimal to binary and then convert to inverse of binary by changing 0 to 1 and 1 to 0

public class test {
public static void main(String[] args) {
System.out.println(getIntegerComplement(50));
}
static int getIntegerComplement(int n) {
String binary = "";
String rev ="";
StringBuilder sb = new StringBuilder();
int k;
while(n>0){
int r= n%2;
binary = r+binary;
n= n/2;        
}
System.out.println("binary for n is::"+ binary);
for(int i=0; i<binary.length(); i++) {
sb.append(binary.charAt(i));

if(sb.charAt(i)=='0') {
sb.replace(i, i+1, "1");
}else{
sb.replace(i, i+1, "0");        
}
}
rev = sb.toString();
k = Integer.parseInt(rev);
int decimal=0;
int power=0;
int l=k;
while(l>0) {
int tmp = l%10;
decimal = (int) (decimal+ tmp*Math.pow(2, power));
l=l/10;
power++;
}
System.out.println("decimal of inverse is:::"+ decimal);
System.out.print("inverse binary of n is:::");
return k;


}

}