Top 10 Libraries of Java

by FC Team · Published April 28, 2023 · Updated July 17, 2023

Java’s prominence in the industry stands still due to its vast significant features. Most of the business applications that exist today have Java as their backbone. A java library contains many modules that come under an identical theme. It expands the functionality of the Java code and lets the developer reduce complexities in the code. Apart from the core library that is possessed, there are other extensive Java libraries available in the market. This article will list the most remarkable Java libraries and their functionalities.

Java top 10 libraries:

Some of the popular standard libraries present in Java are java.lang, java.util and java.math, and so on. Apart from these libraries, we can also use the other popular libraries from the list given below:

1. Java Standard Library:

The Java Standard library is the most popular library as it comes with the programming language itself. Many people fail to notice the importance and robustness of the standard library present in Java. Some of the standard libraries include:

a. The java.util class consists of all the data structures and collections in it.

b. java.lang is the most basic library that lets us use many functionalities like various data types in the program code. Thus, if you want to add the String, Int, Double, or any other datatype, you must include the java.lang library.

c. The java.io library is required to get any kind of input from the user and produce output on the screen.

d. To use the built-in mathematical functions, you can use java.math library.

e. The other library that allows us to get inputs as java.io is java.nio library. It stands for non-blocking I/O. we can use this library to perform intensive operations.

2. Apache Commons:

Apache Commons is a general-purpose library or in other words, an open-source project that consists of reusable Java components. Some of the most popular ones are:

Commons BSF
Commons CSV
Commons Crypto
Commons IO
Commons Numbers
Commons Text

Basically, the Apache Commons consists of three parts as below:

a. Commons Proper: It consists of reusable java components.

b. Commons Sandbox: It acts as an environment to develop Java components.

c. Commons Dormant: It is a repository with inactive components.

The Apache Commons has around 40+ modular libraries. Domains like Math, Database, I/O utils, Collections, and Math come under this. It is highly advisable to use Apache Commons for bigger projects.

Features of Apache Commons:

JDBC Helper
Java Classes
I/O Utilities
Logging Utilities
Java Collections Framework extension
Mathematics and Statistics Components

3. Google Guava:

The Google Guava library is an alternative to Apache Commons. It is also a General-purpose library that contains various core Java libraries. It was initially developed by Google, and later many engineers contributed to its growth. Guava has unswervingly been one of the most popular Java libraries. It is categorized into three heads such as:

Google Collections Library
Basic utilities – Implements common methods and functions.
Miscellaneous utilities – provides features for productivity

Features of Apache Guava:

I/O Utilities
String Utilities
Java Collection’s extension framework
Caching
Hashing
Concurrency Utilities

4. Mockito:

When it comes to Unit/integration testing, the concept of mocking is a much more familiar one. In mocking, we can easily test a single class that depends on heavyweight classes or external functionalities such as Database operations or I/O operations. This is done by mocking the behavior of the other external Service calls and focusing only on the class that we need to test.

The developers can test double objects or dummy objects for behavior-driven and test-driven behavior. Irrespective of the size of the project, a popular mocking library is Mockito. With simple API, it provides an effective result during Unit/integration testing. It stands ahead of its competitors as Mockito was voted as the best mocking framework of java by StackOverflow.

Features of Mockito:

Mocking is based on annotation
Provides clean API
Gives a simplified stubbing model
It uses BDDMockito to develop its syntax according to the behavior.
Partial mocking takes place via spying.

5. JUnit:

Another popular testing framework is JUnit. As the name suggests, the developers can easily run unit tests using this framework. Any bug or error must be eradicated from the unit level, therefore being proficient in unit testing is crucial.

It provides annotations and asserts classes to write tests in Java. Using JUnit, we can create various samples of test cases each time the test is run. These test cases should be independent of each other in random order.

6. Jackson libraries:

In the process of software development, it is common that we would come across data in various formats. The data must be loaded or saved in various formats or transferring of data from one format to another must take place. JSON makes this task easier to accomplish as it acts as de facto. There are other data formats like CSV, BSON, CBR, Avro, XML, YAML, Protobuf, etc.

The Jackson JSON library is known as a parser library that transfers the .class file into JSON format of JSON string. In addition to it, it also offers data binding and annotations that convert POJO objects to data. It also generates POJO from data.

Features of Jackson Library:

JSON schema
It provides modules for streaming, data-binding, and annotations
Modules are available for data type Avro, CBOR, Ion, XML, YAML, etc
Supports third-party data types like Yandex, MongoDB, Lombok, and so on.
Standard and collection data types.

7. JAXB:

The full form of JAXB is Java Architecture for XML binding. It is an XML parsing library that lets us bind XML schemas and Java presentations. As the Java Standard Library in Java 9 does not support XML functionalities, this led to the adoption of separate libraries like JAXB to serve the purpose. It supports all W3C XML Schema features.

Features of JAXB:

It aids Java to XML with a dedicated package to look after binding.
Fewer number of schema-derived classes.
Small runtime libraries
Validation capabilities

8. HttpClient:

The Java Development Kit or the JDK does not support HTTP requests. Therefore, to implement HTTP connections, the java.net package is preferred. The other third-party libraries like Apache HttpClient and HttpCore are not simple to use.

In the later versions like the JDK 9, it supports 2.0. The HttpClient library supports both synchronous and asynchronous programming. Developers can also use Apache libraries like httpClient, HttpCode, and HttpAsyncClient.

9. Log4j 2:

Various logging libraries in Java like java.util.logging, Log4j, Log4j 2, and Logback are available. The last two libraries like Log4j 2 and Logback are comparatively powerful. In the case of large projects, the logging libraries may perform as expected. But Log4j 2 and Logback work efficiently with bigger projects.

Features of Log4j 2:

Advanced filtering
Cloud support is present
Plugin architecture
It separates API from the implementation part.
Effective asynchronous logging.

10. DBCP:

The full form of DBCP is Database Connection Pool Library. In most cases, the software is developed in many languages or platforms. Rare is software that is limited to one language or platform. In the former scenario, we need to integrate the databases in Java applications. This is where the role of the Database Connection pool libraries is vital.

With the help of DBPC, the developers need not create separate Database connections as it allows them to pool the required database. It reduces a lot of time and manual work. The upgraded version of DBCP such as Apache DBCP 2 has numerous features and it also supports JMX to pool the resources.

Conclusion:

Developing large projects entirely from scratch without implementing the libraries would seem like a reinventing wheel in the modern era. Therefore, it is essential to know the libraries that can minimize the workload. I hope this article gave you a proper insight into what a library is and a brief idea about the popular Java libraries.