In Java, polymorphism results in code that is more concise and easier to maintain. This tutorial provides an overview of the four types of Java polymorphism, but our focus is subtype polymorphism.

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Even though the reference type is Animal, Java decides at runtime which sound () method to call based on the actual object (Dog or Cat). This is runtime polymorphism (a.k.a. dynamic method dispatch).

For more on that, check out our guide to Android development for beginners. For the purposes of this Java tutorial, it may be easier to write your code directly into a Java compiler app.