How do I list declared methods of a class using Reflection?

Reflection you can interrogate any class and find out all the methods that have been declared. When you call the getDeclaredMethods() method, it will return to you a Method[] array with the objects of methods that have been declared public, protected, private or default(package) in the class.

Getting All Methods for a given Class

Mammal dog = new Mammal();
Class dogClass  = dog.getClass();
Method[] declaredMethods = dogClass.getDeclaredMethods();

Calling the getDeclaredMethods() method will return to you a Method[] array with the objects of methods that have been public in the class.

Iterating through all the Declared Methods

for (Method method : declaredMethods) {
  int mods = method.getModifiers();
   
  System.out.println("  DECLARED METHODS are " + method.getName() 
       + " mods=" + Modifier.toString(mods)
       + " retType=" + method.getReturnType()
      );
}

Full Program Listing

package com.avaldes.tutorials;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Arrays;

public class GetAllDeclaredMethodsExample {

  public static void main(String[] args) {
    Mammal dog = new Mammal();
    Class dogClass = dog.getClass();
  
    System.out.println("\nDetails for " + dogClass.getCanonicalName());
    Method[] publicMethods = dogClass.getDeclaredMethods();
    for (Method method : publicMethods) {
      int mods = method.getModifiers();
      
      System.out.println("  DECLARED METHODS are " + method.getName() 
          + " mods=" + Modifier.toString(mods)
          + " retType=" + method.getReturnType()
          );
    }
  }
}

Full Program Listing (Mammal.java)

package com.avaldes.tutorials;

public class Mammal implements Animal {

  private boolean hair = false;
  private String name = null;
  private static int MammalCount = 0; 
  
  public Mammal() {
    incCount();
  }
  
  public String getName() {
    return name;
  }
  
  public static int getMammalCount() {
    return MammalCount;
  }


  private static void incCount() {
    MammalCount++;
  }

  public void setName(String name) {
    this.name = name;
  }

  private void privateMethod() {
    System.out.println("Private Method!!!");
  }
  
  protected void protectedMethod() {
    System.out.println("Protected Method!!!");
  }
  
  @Override
  public void eat() {
    System.out.println("Mammal is eating...");
  }

  @Override
  public void sleep() {
    System.out.println("Mammal is Sleeping...");
  }

  @Override
  public void walk() {
    System.out.println("Mammal is Walking...");
  }

  public boolean isHair() {
    return hair;
  }

  public void setHair(boolean hair) {
    this.hair = hair;
  }

  public String toString() {
    return "[name=" + getName() + ", hair=" + isHair() 
                    + ", Mammals=" + getMammalCount() + "]";
  }
}

Output

Details for com.avaldes.tutorials.Mammal
  DECLARED METHODS are toString mods=public retType=class java.lang.String
  DECLARED METHODS are getName mods=public retType=class java.lang.String
  DECLARED METHODS are setName mods=public retType=void
  DECLARED METHODS are sleep mods=public retType=void
  DECLARED METHODS are incCount mods=private static retType=void
  DECLARED METHODS are getMammalCount mods=public static retType=int
  DECLARED METHODS are privateMethod mods=private retType=void
  DECLARED METHODS are protectedMethod mods=protected retType=void
  DECLARED METHODS are eat mods=public retType=void
  DECLARED METHODS are walk mods=public retType=void
  DECLARED METHODS are isHair mods=public retType=boolean
  DECLARED METHODS are setHair mods=public retType=void

Java Reflection Examples

  • Class Example
    Simple example shows you how to dynamically load and instantiate a class, get class name, package name, and superclass name.
  • Modifier Example
    Showing you how to get information about classes, fields and methods using modifier method.
  • Method Example
    Providing full details of how to get all methods, and invoke methods using reflection.

Frequently Asked Questions on Java Reflection API (FAQs)

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