Skip to content
Related Articles

Related Articles

Improve Article

Class getDeclaredField() method in Java with Examples

  • Last Updated : 16 Dec, 2019

The getDeclaredField() method of java.lang.Class class is used to get the specified field of this class. The method returns the specified field of this class in the form of Field object.

Syntax:

public Field getDeclaredField(String fieldName)
       throws NoSuchMethodException,
              SecurityException

Parameter: This method accepts a parameter fieldName which is the Field to get.

Return Value: This method returns the specified field of this class in the form of Field objects.

Exception This method throws:



  • NoSuchFieldException if a field with the specified name is not found.
  • NullPointerException if name is null
  • SecurityException if a security manager is present and the security conditions are not met.

    Below programs demonstrate the getDeclaredField() method.

    Example 1:




    // Java program to demonstrate
    // getDeclaredField() method
      
    import java.util.*;
      
    public class Test {
      
        public Object obj;
      
        public static void main(String[] args)
            throws ClassNotFoundException, NoSuchFieldException
        {
      
            // returns the Class object for this class
            Class myClass = Class.forName("Test");
      
            System.out.println("Class represented by myClass: "
                               + myClass.toString());
      
            String fieldName = "obj";
      
            // Get the field of myClass
            // using getDeclaredField() method
            System.out.println(
                fieldName + " Field of myClass: "
                + myClass.getDeclaredField(fieldName));
        }
    }
    Output:
    Class represented by myClass: class Test
    obj Field of myClass: public java.lang.Object Test.obj
    

    Example 2:




    // Java program to demonstrate
    // getDeclaredField() method
      
    import java.util.*;
      
    class Main {
      
        private Object obj;
      
        public static void main(String[] args)
            throws ClassNotFoundException, NoSuchFieldException
        {
      
            // returns the Class object for this class
            Class myClass = Class.forName("Main");
      
            System.out.println("Class represented by myClass: "
                               + myClass.toString());
      
            String fieldName = "obj";
      
            try {
                // Get the field of myClass
                // using getDeclaredField() method
                System.out.println(
                    fieldName + " Field of myClass: "
                    + myClass.getDeclaredField(fieldName));
            }
            catch (Exception e) {
                System.out.println(e);
            }
        }
    }
    Output:
    Class represented by myClass: class Main
    obj Field of myClass: private java.lang.Object Main.obj
    

    Reference: https://docs.oracle.com/javase/9/docs/api/java/lang/Class.html#getDeclaredField-java.lang.String-

    Attention reader! Don’t stop learning now. Get hold of all the important Java Foundation and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready. To complete your preparation from learning a language to DS Algo and many more,  please refer Complete Interview Preparation Course.




    My Personal Notes arrow_drop_up
Recommended Articles
Page :