The Class.getComponentType() method call returns the Class representing the component type of an array. If this class does not represent an array class this method returns null reference instead.

package org.kodejava.example.lang.reflect;

public class ComponentTypeDemo {
    public static void main(String[] args) {
        String[] words = {"and", "the"};
        int[][] matrix = {{1, 1}, {2, 1}};
        Double number = 10.0;

        Class clazz = words.getClass();
        Class cls = matrix.getClass();
        Class clz = number.getClass();

        //
        // Gets the type of an array component.
        //
        Class type = clazz.getComponentType();
        System.out.println("Words type: " +
                type.getCanonicalName());

        //
        // Gets the type of an array component.
        //
        Class matrixType = cls.getComponentType();
        System.out.println("Matrix type: " +
                matrixType.getCanonicalName());

        //
        // It will return null if the class doesn't represent
        // an array.
        //
        Class numberType = clz.getComponentType();
        if (numberType != null) {
            System.out.println("Number type: " +
                    numberType.getCanonicalName());
        } else {
            System.out.println(number.getClass().getName() +
                    " class is not an array");
        }
    }
}

This program print the following output:

Words type: java.lang.String
Matrix type: int[]
java.lang.Double class is not an array

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Wayan Saryada

Programmer, runner, recreational diver, currently living in the island of Bali, Indonesia. Mostly programming in Java, creating web based application with Spring Framework, Hibernate / JPA.

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