Software development is incomplete without having a programming language. Libraries and APIs are making programming languages strong and powerful. How good and experienced Java developer depends on how extensive knowledge of API, including JDK and third-party libraries developer has. Unlike my previous blogs here I am going to discuss some of the very important Libraries and APIs. Java is incomplete without these Libraries and APIs. In this article I will mention Java Library and APIs overview. In depth will post separately in different article for each. Let’s start

JUnit :

As per one Survey more than 10000 Java Project hosted on GitHub found that use Junit. JUnit is a unit testing framework for the Java programming language. Java programming language. JUnit has been important in the development of test driven development, and is one of a family of unit testing frameworks which is collectively known as xUnit that originated with SUnit. JUnit is linked as a JAR at compile-time.

You can refer this JUnit to get more on Junit.

Mockito :

Mockito is an open source testing framework for Java released under the MIT License. The framework allows the creation of test double objects (mock objects) in automated unit tests for the purpose of test-driven development (TDD) or behavior-driven development. Mockito allows developers to verify the behavior of the system under test (SUT) without establishing expectations beforehand.

You can browse Mockito here : Mockito

JACKSON :

Jackson In computing, Jackson is a high-performance JSON processor for Java. Its developers extol the combination of fast, correct, lightweight, and ergonomic attributes of the library.

Jackson provides multiple approaches to working with JSON, including using binding annotations on POJO classes for simple use cases.

You can browse Jackson repo here : Jackson

Gson :

Gson (also known as Google Gson) is an open-source Java library to serialize and deserialize Java objects to (and from) JSON.

The Gson library was originally developed for internal purposes of Google, and Version 1.0 was later released on May 22, 2008 under the terms of Apache License 2.0. The latest version, 2.9.1, was released on Jul 31, 2022.

You can browser GSON repo here : gson

LOMBOK :

Project Lombok is a java library that automatically plugs into your editor and build tools, spicing up your java.
Never write another getter or equals method again, with one annotation your class has a fully featured builder, Automate your logging variables, and much more. Lombok everyone should learn This make java to more interesting.

Explore Lombok here

Javassist :

Javassist (Java programming assistant) is a Java library providing a means to manipulate the Java bytecode of an application.[1] In this sense Javassist provides the support for structural reflection, i.e. the ability to change the implementation of a class at run time.

Bytecode manipulation is performed at load-time through a provided class loader. Javassist enables Java programs to define a new class at runtime and to modify a class file when the JVM loads it. Unlike other similar bytecode editors, Javassist provides two levels of API: source level and bytecode level. Using the source-level API, programmers can edit a class file without knowledge of the specifications of the Java bytecode; the whole API is designed with only the vocabulary of the Java language. Programmers can even specify inserted bytecode in the form of Java source text; Javassist compiles it on the fly. On the other hand, the bytecode-level API allows the users to directly edit a class file as other editors.

Browse for more details : javaassist

Google Guava :

Google Guava is an open-source set of common libraries for Java, mainly developed by Google engineers.

Google Guava can be roughly divided into three components: basic utilities to reduce manual labor to implement common methods and behaviors, an extension to the Java collections framework (JCF) formerly called the Google Collections Library, and other utilities which provide convenient and productive features such as functional programming, graphs, caching, range objects, and hashing.

You can browse Google Guava here. : Google Guava

Log4j

Apache Log4j 2 is an upgrade to Log4j that provides significant improvements over its predecessor, Log4j 1.x, and provides many of the improvements available in Logback while fixing some inherent problems in Logback’s architecture.

Log4J : Git : https://github.com/apache/logging-log4j2

official website