There are a number of ways to create apps for Android devices, but the recommended method for most developers is to write native apps using Java and the Android SDK. Java for Android apps is both similar and quite different from other types of Java applications.

If you have experience with Java (or a similar language) then you’ll probably feel pretty comfortable diving right into the code and learning how to use the Android SDK to make your app run. But if you’re new to programming or object-oriented languages then you’ll probably want to get familiar with the syntax of the Java language and how to accomplish basic programming tasks before learning how to use the Android SDK.

Java the Programming Language

Programming languages, like regular languages, are different ways to communicate to a computer how you want it to act. Programming languages allow us to instruct a computer step-by-step how to manipulate data, collect input from users, and display things on a screen, among other things.

Way down on a microscopic level, the processor of a computer sends electrical signals back and forth that control how it operates. High level programming languages like Java mean that we can write these instructions in an abstract manner using words and symbols, and the computer will take care of translating these instructions that we can understand all the way down to electrical impulses that the processor can understand.

Source: blog.teamtreehouse.com