How to check the type or object is a map or not?

Using Class.isAssignableFrom method, we can check whether given object is a map or not.

 

Signature

public native boolean isAssignableFrom(Class<?> cls)

'isAssignableFrom' method return true, if the class or interface represented by this Class object is either the same as, or is a superclass or superinterface of, the class or interface represented by the specified Class parameter, else false.

 

Example

public static boolean isMap(final Class<?> clazz) {
	return clazz != null && (Map.class.isAssignableFrom(clazz));
}

 

Above snippet return true, if the given type a map, else false.

 

Find the below working application.

 

MapCheckDemo.java

package com.sample.app.collections;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

public class MapCheckDemo {

	public static boolean isMap(final Class<?> clazz) {
		return clazz != null && (Map.class.isAssignableFrom(clazz));
	}

	public static void main(String[] args) {
		final Object obj1 = Arrays.asList(2, 3, 5, 7);
		final Object obj2 = new HashMap<>();

		System.out.println("Is obj1 map : " + isMap(obj1.getClass()));
		System.out.println("Is obj2 map : " + isMap(obj2.getClass()));
	}

}

 

Output

Is obj1 map : false
Is obj2 map : true

 

   

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