parseBigInteger( str )The result is a BigInteger object,
which can't be used in normal numeric expressions, but has a number
of methods defined on it for comparison, arithmetic,
bit manipulation etc.
See the
java.math.BigInteger javadocs for details.
str (String)strparseBigInteger("-20000000000000000023").doubleValue()
= -2e19parseBigInteger("18446744073709551616").testBit(64)
= trueBigInteger parseBigInteger(String)