Provides classes for performing arbitrary-precision integer arithmetic ( BigInteger ) and arbitrary-precision decimal arithmetic ( BigDecimal ). BigInteger is analogous to the primitive integer types except that it provides arbitrary precision, hence operations on BigInteger s do not overflow or lose precision. In addition to standard arithmetic operations, BigInteger provides modular arithmetic, GCD calculation, primality testing, prime generation, bit manipulation, and a few other miscellaneous operations. BigDecimal provides arbitrary-precision signed decimal numbers suitable for currency calculations and the like. BigDecimal gives the user complete control over rounding behavior, allowing the user to choose from a comprehensive set of eight rounding modes.