Method Class | isDefault() Method in Java
The java.lang.reflect.Method.isDefault() method is used to check whether the method of the Method object is a Default Method: or not. It returns true if method object is a default method, otherwise it will return false.
Default Method: A public non-abstract on-static method with a body declared in an interface type.
Syntax:
public boolean isDefault()
Return Value: This method returns a boolean value. It returns true if method object is a default method by JVM Specifications, else false.
Below program illustrates isDefault() method of Method class:
Example 1:
/** Program Demonstrate isDefault() method * of Method Class.*/import java.lang.reflect.Method;public class GFG {      // create main method    public static void main(String args[])    {          try {              // create class object for interface Shape            Class c = Shape.class;              // get list of Method object            Method[] methods = c.getMethods();              // print Default Methods            for (Method m : methods) {                  // check whether the method is Default Method or not                if (m.isDefault())                    // Print                    System.out.println("Method: "                                       + m.getName()                                       + " is Default Method");            }        }        catch (Exception e) {            e.printStackTrace();        }    }      private interface Shape {    default int        draw()        {            return 0;        }          void paint();    }} |
Output:
Method: draw is Default Method
Example 2:
/** Program Demonstrate isDefault() method * of Method Class.* This program checks all default method in Comparator interface*/import java.lang.reflect.Method;import java.util.Comparator;public class Main6 {      // create main method    public static void main(String args[])    {          try {              // create class object for Interface Comparator            Class c = Comparator.class;              // get list of Method object            Method[] methods = c.getMethods();              System.out.println("Default Methods of Comparator Interface");            for (Method method : methods) {                // check whether method is Default Method or not                if (method.isDefault())                    // print Method name                    System.out.println(method.getName());            }        }        catch (Exception e) {            e.printStackTrace();        }    }} |
Output:
Default Methods of Comparator Interface reversed thenComparing thenComparing thenComparing thenComparingInt thenComparingLong thenComparingDouble
Reference:
https://docs.oracle.com/javase/8/docs/api/java/lang/reflect/Method.html#isDefault–
