Learn Java For App Development - A Complete Guide

Java is one of the powerful general-purpose programming languages, created in 1995 by Sun Microsystems (now owned by Oracle). Java is Object-Oriented. However, it is not considered as pure object-oriented as it provides support for primitive data types (like int, char, etc). Java syntax is similar to C/C++. But Java does not provide low-level programming functionalities like pointers. Also, Java code is always written in the form of classes and objects.

Android heavily relies on the Java programming language all the SDK s required to build for Android applications use the standard libraries of Java. If one is coming from a traditional programming background like C, C++, Java is easy to learn. So in this discussion, there is a complete guide to learning Java specifically considering Android App Development.

Java for Android App Development

Here's a list highlighting reasons why Java is chosen for Android app development:

• Established Ecosystem: Java has been the primary language for Android development since the platform's inception, resulting in a vast ecosystem of libraries, frameworks, and tools specifically tailored for Android.
• Wide Adoption and Support: Java is one of the most widely used programming languages globally, ensuring a large community of developers, extensive documentation, and abundant resources for learning and troubleshooting.
• Mature Tooling: Android Studio, the official IDE for Android development, provides robust support for Java. It includes advanced features like code completion, debugging tools, and integration with the Android SDK, making development efficient and productive.
• Performance: Java's runtime performance is well-understood and optimized for Android devices. It offers predictable performance characteristics, making it suitable for developing high-performance applications.
• Backward Compatibility: Java's backward compatibility ensures that older Android devices can run apps developed with newer versions of the language, reducing fragmentation issues.
• Enterprise Support: Many large enterprises and organizations have extensive Java codebases and expertise, making Java a natural choice for maintaining and extending existing Android applications..
• Integration with Native Code: Java allows seamless integration with C/C++ code through the Java Native Interface (JNI), enabling developers to leverage existing native libraries for performance-critical tasks..

Basics of Java

• How to start learning Java - understand the core introduction of the Java programming language.
• Setting up the environment - Setup IDE for writing programs in Java.
• The Hello World Example - The first Hello World program in Java.
• Java Class File - Basic entry point of Java programming, which is writing the main class.
• Java Identifiers - In Java, an identifier can be a class name, method name, variable name, or label.
• Data types in Java - Get to know what types of data types are supported by the Java programming language.
• Variables in Java - A variable is a name given to a memory location. It is the basic unit of storage in a program.
• Scope of Variables - The scope of a variable is the part of the program where the variable is accessible.
• Blank Final in Java - A final variable in Java can be assigned a value only once. We can assign a value either in the declaration or later.

Decision Making Statements in Java

• Decision Making in Java (if, if-else, switch, break, continue, jump) - A programming language uses control statements to control the flow of execution of a program based on certain conditions.
• Switch Statement in Java - The switch statement is a multi-way branch statement. It provides an easy way to dispatch execution to different parts of code based on the value of the expression.
• Loops in Java - Looping in programming languages is a feature that facilitates the execution of a set of instructions/functions repeatedly while some conditions are evaluated to be true.
• For-each loop in Java - For-each is another array traversing technique like for loop, while loop, do-while loop is introduced in Java5.

Type Conversion in Java

• Type conversion in Java with Examples - If the data types are compatible, then Java will perform the conversion automatically known as Automatic Type Conversion, and if not, then they need to be cast or converted explicitly.

Comments in Java

• Comments in Java - Comments take part in making the program become more human-readable by placing the details of code involved and proper use of comments makes maintenance easier and finding bugs easier.

Operators in Java

• Operators in Java - Java provides many types of operators which can be used according to the need. They are classified based on the functionality they provide.

Strings in Java

• String class in Java | Set 1 - String is a sequence of characters. In Java, objects of strings are immutable, which means constant and cannot be changed once created.
• StringBuffer class in Java - StringBuffer is a peer class of String that provides much of the functionality of strings.
• StringBuilder Class in Java with Examples - The StringBuilder in Java represents a mutable sequence of characters.

Object-Oriented Programming Concepts in Java

• Classes and Objects in Java - The basic OOPs components Class and Object in the java programming language.
• Different ways to create objects in Java - Get to know the various ways of creating objects in Java.
• Inheritance in Java - It is the mechanism in Java by which one class is allowed to inherit the features(fields and methods) of another class.
• Encapsulation in Java - Encapsulation is defined as the wrapping up of data under a single unit.
• Abstraction in Java - Data Abstraction is a property by virtue of which only the essential details are displayed to the user.
• Access Modifiers in Java - As the name suggests, access modifiers in Java help to restrict the scope of a class, constructor, variable, method, or data member.
• ‘this’ reference in Java - ‘this’ is a reference variable that refers to the current object.
• Overloading in Java - Overloading allows different methods to have the same name, but different signatures of methods.
• Overriding in Java - Overriding is a feature that allows a subclass or child class to provide a specific implementation of a method that is already provided by one of its super-classes or parent classes.
• Object class in Java - Object class is present in the java.lang package. Every class in Java is directly or indirectly derived from the Object class.
• Static class in Java - Some classes can be made static in Java. Java supports Static Instance Variables, Static Methods, Static Block, and Static Classes.

Exception Handling in Java

• Exceptions in Java - An exception is an unwanted or unexpected event that occurs during the execution of a program i.e at run time.
• Types of Exception in Java with Examples - Java also allows users to define their own exceptions.

Interfaces and Abstract Classes

• Interfaces in Java - Like a class, an interface can have methods and variables, but the methods declared in an interface are by default abstract.
• Access specifier of methods in interfaces - All methods in an interface are public, even if we do not specify public with method names. Also, data fields are public static final even if we do not mention them in field names.
• Access specifiers for classes or interfaces in Java - Methods and data members of a class/interface can have one of the following four access specifiers.
• Abstract Classes in Java - Java, a separate keyword abstract is used to make a class abstract.
• Difference between Abstract Class and Interface in Java - Get to know the differences between the interfaces and abstract classes.
• Anonymous Inner Class in Java - It is an inner class without a name and for which only a single object is created.

Essential collections in Java required for Android Development

• ArrayList in Java - ArrayList is a part of the collection framework and is present in the java.util package. It provides us with dynamic arrays in Java.
• HashMap in Java with Examples - It stores the data in (Key, Value) pairs, and you can access it via an index of another type.

Miscellaneous

• Java Naming Conventions - Naming conventions must be followed while developing software in Java for good maintenance and readability of code.
• Generics in Java - Generics mean parameterized types. The idea is to allow types ( Ingers, strings, … etc, and user-defined types) to be a parameter for methods, classes, and interfaces.
• Annotations in Java - Annotations are used to provide supplemental information about a program.
• Lambda Expressions in Java 8 - Lambda expressions basically express instances of functional interfaces (An interface with a single abstract method is called a functional interface.

Conclusion

Java is fundamental for Android app development, providing reliability, versatility, and a robust support network. It ensures consistent performance across diverse devices, empowering developers to innovate effectively in creating impactful applications. So, if you are looking for the complete guide for Java for Android development, then this tutorial is give all the resource that will help you to learn Java fundamental for Android development.