// Use ShowBits as a local class.
class LocalClassDemo {
  public static void main(String args[]) {
    
    // An inner class version of ShowBits.
    class ShowBits {
      int numbits;
      
      ShowBits(int n) {
        numbits = n;
      }
      
      void show(long val) {
        long mask = 1;
        
        // left-shift a 1 into the proper position
        mask <<= numbits-1;
        
        int spacer =0;
        for(; mask != 0; mask >>>= 1) {
          if((val & mask) != 0) System.out.print("1");
          else System.out.print("0");
          spacer++;
          if((spacer % 8) == 0) {
            System.out.print(" ");
            spacer = 0;
          }
        }
        System.out.println();
      }
    }
    
    for(byte b = 0; b < 10; b++) {
      ShowBits byteval = new ShowBits(8);
      
      System.out.print(b + " in binary: ");
      byteval.show(b);
    }
  }
}

Use ShowBits as a local class