Job Ready Java

Lesson 34Using the BigDecimal Class

In this lesson, we will look at the BigDecimal class. This class is used to represent arbitrary precision decimal numbers. It provides ways to set the number of significant digits and configure how numbers should be rounded. This class should be used for all calculations involving currency.

Like some of the other classes and libraries we have covered, we will introduce you to BigDecimal and show what you need to get started. We won't cover every capability of the class, but we will give you enough information so that you can explore the remaining capabilities on your own.

LESSON OBJECTIVES

By the end of this lesson, you will be able to:

• Explain BigDecimal
• Describe scale as it applies to BigDecimal
• Explain considerations for rounding modes

EXPLORING BIGDECIMAL

The Javadoc documentation for BigDecimal is pretty technical and can be a bit intimidating. In this section, we explore some of the ideas behind BigDecimal, and in the next section, we look at some code samples.

BigDecimal is an immutable type (just like String). That means that a BigDecimal object's value cannot be changed once it is set. From a practical standpoint, that means you must set the result of any BigDecimal operation to another BigDecimal variable. We will see examples of this in the code examples later in this lesson.

Constructing BigDecimals

There are several different constructors that you can use to create instances of BigDecimal. Most of them are straightforward, ...