My Java 8 lambda solution...

    //Write your code here
    Arrays.sort( s, (as,bs) -> {BigDecimal bd = new BigDecimal(bs); 
       return bd.compareTo(new BigDecimal(as));} );

FAILED with...

Exception in thread "main" java.lang.NullPointerException
  at java.math.BigDecimal.<init>(BigDecimal.java:806)
  at Solution.lambda`$main$`0(Solution.java:17)

BECAUSE the provided code declared the array too large!

    // REPLACE:
    // String []s=new String[n+2];

    // WITH:
       String []s=new String[n];

With the above fix, it now passes all TC's.