Don't do int division since this always will result in a truncated int. Instead have your division use at least one double value.

double num = 4.0/3.0;

Then when you want to display it as a String, format the output so you can choose your decimal places:

// one way to do it
// %.3f is for a floating number with 3 digits to the right of the decimal
// %n is for new line
System.out.printf("%.3f%n", num); 

Another:
DecimalFormat decimalFormat = new DecimalFormat("0.000");
System.out.println(decimalFormat.format(num));

That's because you are multiplying by 100 to show a percentage. You should divide with a scale of 4 instead of 2, then set the scale to 2:

new BigDecimal(193251715).divide(new BigDecimal(659669075), 4, RoundingMode.HALF_UP)
                         .multiply(new BigDecimal(100))
                         .setScale(2)

Well this one works...

double roundOff = Math.round(a * 100.0) / 100.0;

Output is

123.14

Or as @Rufein said

 double roundOff = (double) Math.round(a * 100) / 100;

this will do it for you as well.

If you want 2 / 3 to result in 66.67, you need to multiply first, then divide and round to 2 decimal places:

BigDecimal totalPrep = BigDecimal.valueOf(2);
BigDecimal totalCase = BigDecimal.valueOf(3);

BigDecimal result = totalPrep.multiply(BigDecimal.valueOf(100))
                             .divide(totalCase, 2, RoundingMode.HALF_UP);

System.out.println(result); // prints: 66.67

That will calculate 2 * 100 = 200, then 200 / 3 = 66.67 (rounded)

When you divide first, you calculate 2 / 3 = 0.67 (rounded), then 0.67 * 100 = 67.00, which is obviously not what you want.

Use DecimalFormat API

        double d = amount / 100 * 7;
        DecimalFormat df = new DecimalFormat("#.##");
        System.out.print(df.format(d));

"##" denotes the 2 digit precision