Java Guava | Longs.join() method with Examples

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

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

class GFG {

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

        // Creating a long array
        long[] arr = { 2, 4, 6, 8, 10 };

        // Using Longs.join() method to get a
        // string containing the elements of array
        // separated by a separator
        System.out.println(Longs.join("#", arr));
    }
}
Output:
2#4#6#8#10
Example 2: Java
// Java code to show implementation of
// Guava's Longs.join() method

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

class GFG {

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

        // Creating a long array
        long[] arr = { 3, 5, 7, 9, 11 };

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