The String.format syntax helps us convert doubles and BigDecimals to strings of whatever precision.
This java code:
double dennis = 0.00000008880000d;
System.out.println(dennis);
System.out.println(String.format("%.7f", dennis));
System.out.println(String.format("%.9f", new BigDecimal(dennis)));
System.out.println(String.format("%.19f", new BigDecimal(dennis)));
Prints:
8.88E-8
0.0000001
0.000000089
0.0000000888000000000