== what the JDK gives for 123456789 ==
String.format(en_IN, "%,d")      : 123,456,789
String.format(hi_IN, "%,d")      : 123,456,789
NumberFormat.getInstance(en_IN)   : 123,456,789
NumberFormat currency (en_IN)     : ₹123,456,789.50
CLDR pattern for en_IN            : #,##0.###

== a DecimalFormat pattern that LOOKS like it should work ==
pattern #,##,##0 -> grouping size : 3
pattern #,##,##0 -> output        : 123,456,789

== compact formatting knows crore but drops the digits ==
compact (default rounding)        : 12Cr
compact (2 fraction digits)       : 12.35Cr

== IndianNumberFormat ==
              0  ->  0
            999  ->  999
          1,000  ->  1,000
         12,345  ->  12,345
        123,456  ->  1,23,456
      1,234,567  ->  12,34,567
    123,456,789  ->  12,34,56,789
   -123,456,789  ->  -12,34,56,789
12,34,567.89
-1,00,000.00
Rs. 12,34,567.50

== plugging it into a format string through %s ==
Balance            9,87,65,432.10