Constructor isVarArgs() method in Java with Examples

The isVarArgs() method of java.lang.reflect.Constructor class is used to return the boolean value true if this Constructor can take a variable number of arguments as parameters else method will return false.VarArgs allows the constructor to accept a number of arguments. using VarArgs is a better approach to pass arguments than array when it is not known how many arguments to pass in the constructor.

Syntax:

public boolean isVarArgs()

Parameters: This method accepts nothing. 

Return: This method returns true if and only if this executable was declared to take a variable number of arguments. 

Below programs illustrate isVarArgs() method: 

Program 1:

Java

// Java program to illustrate isVarArgs() method

import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;

public class GFG {

    public static void main(String[] args)
    {
        // create a class object
        Class classObj = shape.class;

        // get Constructor object
        // array from class object
        Constructor[] cons = classObj.getConstructors();

        // check isVarArgs or not
        boolean isVargs = cons[0].isVarArgs();

        // print result
        System.out.println("isVargs : " + isVargs);
    }

    public class shape {

        public shape(Object... objects)
        {
        }
    }
}

Output:

isVargs : true

Program 2:

Java

// Java program to illustrate isVarArgs() method

import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;

public class GFG {

    public static void main(String[] args)
    {
        // create a class object
        Class classObj = String.class;

        // get Constructor object
        // array from class object
        Constructor[] cons = classObj.getConstructors();

        for (int i = 0; i < cons.length; i++) {
            // check isVarArgs or not
            boolean isVargs = cons[i].isVarArgs();

            // print result
            System.out.println(cons[i]);
            System.out.println("isVargs : " + isVargs);
        }
    }
}

Output:

public java.lang.String(byte[], int, int) isVargs : false public java.lang.String(byte[], java.nio.charset.Charset) isVargs : false public java.lang.String(byte[], java.lang.String) throws java.io.UnsupportedEncodingException isVargs : false public java.lang.String(byte[], int, int, java.nio.charset.Charset) isVargs : false public java.lang.String(byte[], int, int, java.lang.String) throws java.io.UnsupportedEncodingException isVargs : false public java.lang.String(java.lang.StringBuilder) isVargs : false public java.lang.String(java.lang.StringBuffer) isVargs : false public java.lang.String(byte[]) isVargs : false public java.lang.String(int[], int, int) isVargs : false public java.lang.String() isVargs : false public java.lang.String(char[]) isVargs : false public java.lang.String(java.lang.String) isVargs : false public java.lang.String(char[], int, int) isVargs : false public java.lang.String(byte[], int) isVargs : false public java.lang.String(byte[], int, int, int) isVargs : false

References: https://docs.oracle.com/javase/10/docs/api/java/lang/reflect/Constructor.html#isVarArgs()