Converting String to BigDecimal in Java

Last updated: January 8, 2024

Written by: baeldung

Reviewed by: Michal Aibin

Java String

Azure Container Apps is a fully managed serverless container service that enables you to build and deploy modern, cloud-native Java applications and microservices at scale. It offers a simplified developer experience while providing the flexibility and portability of containers.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, visit the documentation page.

You can also ask questions and leave feedback on the Azure Container Apps GitHub page.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, you can get started over on the documentation page.

And, you can also ask questions and leave feedback on the Azure Container Apps GitHub page.

Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

With Orkes Conductor managed through Orkes Cloud, developers can focus on building mission critical applications without worrying about infrastructure maintenance to meet goals and, simply put, taking new products live faster and reducing total cost of ownership.

Try a 14-Day Free Trial of Orkes Conductor today.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

Try a 14-Day Free Trial of Orkes Conductor today.

End-to-end testing is a very useful method to make sure that your application works as intended. This highlights issues in the overall functionality of the software, that the unit and integration test stages may miss.

Playwright is an easy-to-use, but powerful tool that automates end-to-end testing, and supports all modern browsers and platforms.

When coupled with LambdaTest (an AI-powered cloud-based test execution platform) it can be further scaled to run the Playwright scripts in parallel across 3000+ browser and device combinations:

>> Automated End-to-End Testing With Playwright

1. Overview

In this tutorial, we’ll cover many ways of converting String to BigDecimal in Java.

2. BigDecimal

BigDecimal represents an immutable arbitrary-precision signed decimal number. It consists of two parts:

Unscaled value – an arbitrary precision integer
Scale – a 32-bit integer representing the number of digits to the right of the decimal point

For example, the BigDecimal 3.14 has an unscaled value of 314 and a scale of 2.

If zero or positive, the scale is the number of digits to the right of the decimal point.

If negative, the unscaled value of the number is multiplied by ten to the power of the negation of the scale. Therefore, the value of the number represented by the BigDecimal is (Unscaled value × 10^-Scale).

The BigDecimal class in Java provides operations for basic arithmetic, scale manipulation, comparison, format conversion, and hashing.

Furthermore, we use BigDecimal for high-precision arithmetic, calculations requiring control over the scale, and rounding off behavior. One such example is calculations involving financial transactions.

We can convert a String into BigDecimal in Java using one of the below methods:

BigDecimal(String) constructor
BigDecimal.valueOf() method
DecimalFormat.parse() method

Let’s discuss each of them below.

3. BigDecimal(String)

The easiest way to convert String to BigDecimal in Java is to use BigDecimal(String) constructor:

BigDecimal bigDecimal = new BigDecimal("123");
assertEquals(new BigDecimal(123), bigDecimal);

4. BigDecimal.valueOf()

We can also convert String to BigDecimal by using the BigDecimal.valueOf(double) method.

This is a two-step process. The first step is to convert the String to Double. The second step is to convert Double to BigDecimal:

BigDecimal bigDecimal = BigDecimal.valueOf(Double.valueOf("123.42"));
assertEquals(new BigDecimal(123.42).setScale(2, BigDecimal.ROUND_HALF_UP), bigDecimal);

It must be noted that some floating-point numbers can’t be exactly represented using a Double value. This is because of the in-memory representation of floating-point numbers of type Double. Indeed, the number is represented in a rational form approaching the entered Double number as much as possible. As a result, some floating-point numbers become inaccurate.

5. DecimalFormat.parse()

When a String representing a value has a more complex format, we can use a DecimalFormat.

For example, we can convert a decimal-based long value without removing non-numeric symbols:

BigDecimal bigDecimal = new BigDecimal(10692467440017.111).setScale(3, BigDecimal.ROUND_HALF_UP);

DecimalFormatSymbols symbols = new DecimalFormatSymbols();
symbols.setGroupingSeparator(',');
symbols.setDecimalSeparator('.');
String pattern = "#,##0.0#";
DecimalFormat decimalFormat = new DecimalFormat(pattern, symbols);
decimalFormat.setParseBigDecimal(true);

// parse the string value
BigDecimal parsedStringValue = (BigDecimal) decimalFormat.parse("10,692,467,440,017.111");

assertEquals(bigDecimal, parsedStringValue);

The DecimalFormat.parse method returns a Number, which we convert to a BigDecimal number using the setParseBigDecimal(true).

Usually, the DecimalFormat is more advanced than we require. Thus, we should favor the new BigDecimal(String) or the BigDecimal.valueOf() instead.

6. Invalid Conversions

Java provides generic exceptions for handling invalid numeric Strings.

Notably, new BigDecimal(String), BigDecimal.valueOf(), and DecimalFormat.parse throw a NullPointerException when we pass null:

@Test(expected = NullPointerException.class)
public void givenNullString_WhenBigDecimalObjectWithStringParameter_ThenNullPointerExceptionIsThrown() {
    String bigDecimal = null;
    new BigDecimal(bigDecimal);
}

@Test(expected = NullPointerException.class)
public void givenNullString_WhenValueOfDoubleFromString_ThenNullPointerExceptionIsThrown() {
    BigDecimal.valueOf(Double.valueOf(null));
}

@Test(expected = NullPointerException.class)
public void givenNullString_WhenDecimalFormatOfString_ThenNullPointerExceptionIsThrown()
  throws ParseException {
    new DecimalFormat("#").parse(null);
}

Similary, new BigDecimal(String) and BigDecimal.valueOf() throw a NumberFormatException when we pass an invalid String that can’t be parsed to a BigDecimal (such as &):

@Test(expected = NumberFormatException.class)
public void givenInalidString_WhenBigDecimalObjectWithStringParameter_ThenNumberFormatExceptionIsThrown() {
    new BigDecimal("&");
}

@Test(expected = NumberFormatException.class)
public void givenInalidString_WhenValueOfDoubleFromString_ThenNumberFormatExceptionIsThrown() {
    BigDecimal.valueOf(Double.valueOf("&"));
}

Lastly, DecimalFormat.parse throws a ParseException when we pass an invalid String:

@Test(expected = ParseException.class)
public void givenInalidString_WhenDecimalFormatOfString_ThenNumberFormatExceptionIsThrown()
  throws ParseException {
    new DecimalFormat("#").parse("&");
}

7. Conclusion

In this article, we learned that Java provides us with multiple methods to convert String to BigDecimal values. In general, we recommend using the new BigDecimal(String) method for this purpose.

The code backing this article is available on GitHub. Once you're logged in as a Baeldung Pro Member, start learning and coding on the project.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, visit the documentation page.

You can also ask questions and leave feedback on the Azure Container Apps GitHub page.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

Try a 14-Day Free Trial of Orkes Conductor today.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

Try a 14-Day Free Trial of Orkes Conductor today.