In this article, we will review Java for Android and Android application development. This article is very suitable for people who are familiar with at least one programming language such as PHP. In this tutorial, you will get to know the basics of Java, including object-oriented programming.
We’re going to provide clear examples of common Java language principles, while also mentioning some Android-specific tips and tricks.
To develop Android apps (or any Java app), you need a software development environment to write and build applications. Eclipse is a very popular development environment for Java and Android application development; It is available for free for Windows, Mac, and Linux operating systems.
Table of Contents
What is Java?
Java is a very popular programming language developed by Sun Microsystems (now owned by Oracle). Android applications are also developed using the Java language. Java was developed long after C and C++ and includes many features of these powerful languages. While some of the bugs are covered.
Programming languages are still only as powerful as their libraries. These libraries are created to help developers build applications.
Some of the main features of Java are:
- Easy to learn and understand
- Being platform independent
- Being object-oriented
- Virtual machines
Android relies heavily on these Java basics. The Android Software Development Kit (SDK) includes many standard Java libraries (data structure libraries, math libraries, graphics libraries, networking libraries, etc.) as well as Android-specific libraries that help you develop applications. Very attractive Android helps.
Why is Java easy to learn?
Java is easy to learn for several reasons. Java is one of the widely discussed, taught, and used programming languages. It is used for all kinds of programming projects, regardless of their scale, from web apps to mobile apps.
In addition, Java is one of the most readable programming languages for humans. It means that a person who does not know programming can also understand its efficiency to some extent by checking its codes.
Why is Java platform independence important?
For many programming languages, you need to use a compiler to make your code understandable to the machine. Different devices use different languages. This means that you may need to compile your apps for each device and with different languages.
But Java is not like that…
Java compilers convert your code from Java source files (readable by humans) into something called “bytecode” (readable by Java). These codes are translated by a Java virtual machine; which works on the code just like a physical processor to execute the compiled code.
Android apps run in a special virtual machine called Dalvik VM. Dalvik VM can be considered as the platform on which the Android application runs. Regardless of the type of device.
Why is Java safe?
Since Java programs run in a virtual machine, they are isolated from the hardware of the device. Thus, the virtual machine can encrypt, maintain, and securely manage code execution compared to languages that work directly with machine code.
Each Android application runs on the operating system (Linux-based) using a different Dalvik VM user account. Android applications are monitored by the operating system and will be stopped if they are not performing well (for example, using too much CPU power, not being responsive, etc.), so it is important to create stable and responsive applications. Applications can communicate with each other using defined protocols.
Compile the codes
To develop Android applications, you must compile them. The Eclipse development environment (with the Android Development plugin) facilitates this. In Eclipse, automatic compilation is often turned on by default. This means that every time you save the project file, Eclipse will recompile the program changes. You can immediately see compilation errors. Eclipse also translates Java, provides coloring and formatting, and displays errors. Often you can click on the error to have Eclipse correct it automatically.
Alternatively, you can compile the code manually if you prefer. In Eclipse, you’ll find the Build settings under the project menu. If you have “Build Automatic” turned on, you can select the “Clean…” option, which will allow you to completely rebuild all files. If “Build Automatic” is off, “Build All” and “Build Project” options are enabled. “Build All” means building all projects in the workspace. You can have many projects in one Eclipse workspace.
What is an object-oriented programming language?
Object-oriented programming is a programming method or technique that relies on defining data structures. In the sense that the data and the functions that operate on this data are as much as possible in a format called “object” and are placed next to each other, summarized, and form a unit (or an object) and compared to the outside environment. They are encapsulated.
For example, let’s say you have a “dog object” that represents a sketch of a dog, with a name, breed, and gender. You can then create different instances of the dog object to represent specific dogs. Each Dog object must be created by calling its constructor.
- Inheritance in Java
Here’s another important concept in Java that you’ll come across a lot: inheritance in Java. Inheritance means that Java classes (and objects) can be hierarchically organized in terms of behavior and properties. In simple words, inheritance in Java is a mechanism by which an object acquires all the features and capabilities of the parent object and inherits it in the term.
- Organization of object behavior with interface
In Java, you can organize the behavior of the object by the interface. While a class defines an object, an interface defines some behavior that can be applied to an object.
- Organize classes and interfaces using packages
Class hierarchies can be organized into packages. A package is a collection of classes and interfaces that are put together.