Java Guava | Doubles.join() method with Examples

Last Updated : 11 Jul, 2025
The join() method of Doubles Class in the Guava library is used to combine or join all the given double values separated by a separator. These double values are passed a parameter to this method. This method also takes the separator as the parameter. This method returns a String which is the result of join operation on the specified double values.
For example: join("-", 1L, 2L, 3L) returns the string "1-2-3".
Syntax:
public static String join(String separator, double... array)
Parameters: This method accepts two mandatory parameters:
  • separator: which is the doubleacter that occurs in between the joined double values.
  • array: which is an array of double values that are to be joined.
Return Value: This method returns a string containing all the given double values separated by separator. Below programs illustrate the use of this method: Example 1: Java
// Java code to show implementation of
// Guava's Doubles.join() method

import com.google.common.primitives.Doubles;
import java.util.Arrays;

class GFG {

    // Driver's code
    public static void main(String[] args)
    {

        // Creating a double array
        double[] arr = { 2.3, 4.2, 6.2, 8.6, 10.5 };

        // Using Doubles.join() method to get a
        // string containing the elements of array
        // separated by a separator
        System.out.println(Doubles.join("#", arr));
    }
}
Output:
2.3#4.2#6.2#8.6#10.5
Example 2: Java
// Java code to show implementation of
// Guava's Doubles.join() method

import com.google.common.primitives.Doubles;
import java.util.Arrays;

class GFG {

    // Driver's code
    public static void main(String[] args)
    {

        // Creating a double array
        double[] arr = { 3.2, 5.4, 7.6, 9.1, 11.2 };

        // Using Doubles.join() method to get a
        // string containing the elements of array
        // separated by a separator
        System.out.println(Doubles.join("*", arr));
    }
}
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