getMethods() vs getDeclaredMethods() in Java reflection

Class.getMethods return the public methods of this class and the public methods inherited from super classes (in simple terms, getMethods ignore non-public methods from this class and super classes.).

 

Class.getDeclaredMethods return all the methods declared in this class.

 

Let’s confirm the same with below example.

 

A.java

package com.sample.app.dto;

public class A {

	public void aPublicMethod() {
		System.out.println("Inside aPublicMethod");
	}

	protected void aProtectedMethod() {
		System.out.println("Inside aProtectedMethod");
	}

	void aDefaultMethod() {
		System.out.println("Inside aDefaultMethod");
	}

	private void aPrivateMethod() {
		System.out.println("Inside aPrivateMethod");
	}

}

 

B.java

package com.sample.app.dto;

public class B extends A{
	public void bPublicMethod() {
		System.out.println("Inside bPublicMethod");
	}

	protected void bProtectedMethod() {
		System.out.println("Inside bProtectedMethod");
	}

	void bDefaultMethod() {
		System.out.println("Inside bDefaultMethod");
	}

	private void bPrivateMethod() {
		System.out.println("Inside bPrivateMethod");
	}
}

ReflectionDemo.java

package com.sample.app;

import java.lang.reflect.Method;

import com.sample.app.dto.A;
import com.sample.app.dto.B;

public class ReflectionDemo {

	private static void printMethodNames(Method[] methods, String message) {
		System.out.println(message);
		for (Method method : methods) {
			System.out.println(method.getName());
		}
		System.out.println("\n");
	}

	public static void main(String[] args) {
		Method[] aMethods = A.class.getMethods();
		Method[] aDeclaredMethods = A.class.getDeclaredMethods();

		Method[] bMethods = B.class.getMethods();
		Method[] bDeclaredMethods = B.class.getDeclaredMethods();

		printMethodNames(aMethods, "A.class.getMethods() : ");
		printMethodNames(aDeclaredMethods, "A.class.getDeclaredMethods() : ");
		printMethodNames(bMethods, "B.class.getMethods() : ");
		printMethodNames(bDeclaredMethods, "B.class.getDeclaredMethods() : ");
	}

}

Output

A.class.getMethods() : 
aPublicMethod
wait
wait
wait
equals
toString
hashCode
getClass
notify
notifyAll


A.class.getDeclaredMethods() : 
aPublicMethod
aProtectedMethod
aDefaultMethod
aPrivateMethod


B.class.getMethods() : 
bPublicMethod
aPublicMethod
wait
wait
wait
equals
toString
hashCode
getClass
notify
notifyAll


B.class.getDeclaredMethods() : 
bPublicMethod
bProtectedMethod
bDefaultMethod
bPrivateMethod

 

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