The java.lang.reflect.Method.isVarArgs() method of Method class checks whether Method Object was declared to take a variable number of arguments or not. If the method can take a variable number of arguments then returns true otherwise it will return false. VarArgs(variable-length arguments): VarArgs allows method to accept a number of arguments. It is a better approach to pass arguments than array when it is not known how many arguments to pass in method.
Syntax:
public boolean isVarArgs()
Return Value: This method returns true if and only if Method has variable-length arguments else false.
Below programs illustrates isVarArgs() method of Method class:
Example 1: Below program checks GFG class methods whether Method has variable-length arguments or not. In this program a method accepts VarArgs and by isVarArgs() check method accept VarArgs or not and at last print the result.
Java
// Program Demonstrate isVarArgs() method// of Method Class.import java.lang.reflect.Method;public class GFG { // create another method public static void paint(Object... values) { String message = "A Computer Science portal for geeks"; } // create main method public static void main(String args[]) { try { // get list of declared method objects of class GFG Method[] methods = GFG.class.getMethods(); // loop through method list for (Method method : methods) { // check method contains VarArgs or not boolean isVarArgs = method.isVarArgs(); // print result if VarArgs are present if (isVarArgs) System.out.println(method + " method accepts VarArgs :" + isVarArgs); } } catch (Exception e) { // Print Exception if any Exception occurs e.printStackTrace(); } }} |
public static void GFG.paint(java.lang.Object[]) method accepts VarArgs :true
Example 2: This program is going to return all the Methods which contains variable-length arguments of class java.util.Collections. Explanation: In this Method at first java.util.Collections Class Object is created. After creating Class Object of java.util.Collections Class a list of Method Objects is created by calling getMethods() of class Object. Iterate through Method list and get Method contains variable-length arguments using isVarArgs(). At last print Synthetic Method name.
Java
// Program Demonstrate isVarArgs() method// of Method Class.import java.lang.reflect.Method;import java.util.Collections;public class GFG { // create main method public static void main(String args[]) { try { // create class object for class Collections Class c = Collections.class; // get list of Method object Method[] methods = c.getMethods(); System.out.println("Methods of Collections Class" + " contains VarArgs"); // Loop through Methods list for (Method m : methods) { // check whether the method contains VarArgs or not if (m.isVarArgs()) // Print Method name System.out.println("Method: " + m.getName()); } } catch (Exception e) { // print Exception if any Exception occurs e.printStackTrace(); } }} |
Methods of Collections Class contains VarArgs Method: addAll
Reference:
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