Math

The math package provides two new classes: BigInteger and BigDecimal. BigInteger numbers are immutable arbitrary-precision integers, which provide analogs to all of Java's primitive integer operators, and all relevant static methods from java.lang.Math. Additionally, BigInteger numbers provide operations for modular arithmetic, GCD calculation, primality testing, prime generation, single-bit manipulation, and a few other odds and ends.
BigDecimal numbers are immutable, arbitrary-precision signed decimal numbers, suitable for monetary calculations. BigDecimal numbers provide operations for basic arithmetic, scale manipulation, comparison, format conversion and hashing.

Math API Reference
(javadoc)

• java.math Package