1. Overview

In this tutorial, we’ll learn what [Ljava.lang.Object means and how to access the proper values of the object.

2. Java Object Class

In Java, if we want to print a value directly from an object, the first thing that we could try is to call its toString method:

Object[] arrayOfObjects = { "John", 2, true };
assertTrue(arrayOfObjects.toString().startsWith("[Ljava.lang.Object;"));

If we run the test, it will be successful, but usually, it’s not a very useful result.

What we want to do is print the values inside the array. Instead, we have [Ljava.lang.Object. The name of the class, as implemented in Object.class:

getClass().getName() + '@' + Integer.toHexString(hashCode())

When we get the class name directly from the object, we are getting the internal names from the JVM with their types, that’s why we have extra characters like [ and L, they represent the Array and the ClassName types, respectively.

#java #developer