The java.math.BigDecimal.round(MathContext m) is an inbuilt method in Java that returns a BigDecimal value rounded according to the MathContext settings. If the precision setting is 0 then no rounding takes place.
Syntax:
public BigDecimal round(MathContext m)
Parameters: The method accepts a single parameter m which refers to the context to use that is the value up to which the BigDecimal value is to be rounded off.
Return value: This method returns a BigDecimal rounded according to the MathContext settings.
Below programs illustrate the working of java.math.BigDecimal.round(MathContext m) method:
Program 1:
// Java program to demonstrate the// round() methodimport java.math.*;  public class Gfg {      public static void main(String[] args)    {        // Assign value to BigDecimal object b1        BigDecimal b1 = new BigDecimal("4.2585");          MathContext m = new MathContext(4); // 4 precision          // b1 is rounded using m        BigDecimal b2 = b1.round(m);          // Print b2 value        System.out.println("The value of " + b1 +         " after rounding is " + b2);    }} | 
The value of 4.2585 after rounding is 4.259
Program 2:
// Java program to demonstrate the// round() methodimport java.math.*;  public class gfg {      public static void main(String[] args)    {        // Assigning value to BigDecimal object b1        BigDecimal b1 = new BigDecimal("-4.2585");          MathContext m = new MathContext(4); // 4 precision          // b1 is rounded using m        BigDecimal b2 = b1.round(m);          // Print b2 value        System.out.println("The value of " + b1 +         " after rounding is " + b2);    }} | 
The value of -4.2585 after rounding is -4.259
Reference: https://docs.oracle.com/javase/7/docs/api/java/math/BigDecimal.html#round(java.math.MathContext)
