This is convenient! Summary of popular Java library + α

Overview

From the Maven repository ranking (https://mvnrepository.com/open-source), add the top ranking ones and the ones at your own discretion. Description example

1. Library title (link to official page)
2. GitHub page
3. Version information
4. Usage example
5. Maven tag when using (*)

• Note: Please note that the version number of the Maven version tag (version) always changes.

Test framework

• Junit : Java unit test standard library

GitHub：https://github.com/junit-team/junit5 Version information: https://mvnrepository.com/artifact/junit/junit Usage example: https://qiita.com/takehiro224/items/a5d4265c4a1b36b0919c

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
    <scope>test</scope>
</dependency>

• TestNG : A test framework created to make JUnit more convenient. It inherits the functions of JUnit.

GitHub：https://github.com/cbeust/testng Usage example: http://www.mitchy-world.jp/java/test/testng5_01.htm Version information: https://mvnrepository.com/artifact/org.testng/testng

<dependency>
    <groupId>org.testng</groupId>
    <artifactId>testng</artifactId>
    <version>6.14.2</version>
    <scope>test</scope>
</dependency>

• DBunit : Library used for DB testing

Version information: https://mvnrepository.com/artifact/org.dbunit/dbunit Usage example: https://qiita.com/tarosa0001/items/70a1efa9edac2d83ba1a

<dependency>
    <groupId>org.dbunit</groupId>
    <artifactId>dbunit</artifactId>
    <version>2.5.4</version>
</dependency>

log

• SLF4J : Log interface. The implementation library uses Log4j or Logback.

GitHub：https://github.com/qos-ch/slf4j Version information: https://mvnrepository.com/artifact/org.slf4j/slf4j-api

<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId>
    <version>1.7.25</version>
</dependency>

-Log4j: Java log output standard library

GitHub：https://github.com/apache/logging-log4j2 Version information: https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-core Usage example: https://qiita.com/mato-599/items/979e10135c1cb54ceda9

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.11.0</version>
</dependency>

• Logback : Log API along with Log4j. Another logging library created by the developers of Log4j.

GitHub：https://github.com/qos-ch/logback Version information: https://mvnrepository.com/artifact/ch.qos.logback/logback-classic Usage example: https://qiita.com/joe_hrmn/items/356f1e2b05cb90241414 　　　　　https://qiita.com/opengl-8080/items/49719f2d35171f017aa9

<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-classic</artifactId>
    <version>1.2.3</version>
    <scope>test</scope>
</dependency>

mock

• Mockito : Mock library. You can create class-independent objects (mock)

GitHub：https://github.com/mockito/mockito Version information: https://mvnrepository.com/artifact/org.mockito/mockito-core Usage example: https://qiita.com/hitomatagi/items/95ba1bc6a630bac16f9e

<dependency>
    <groupId>org.mockito</groupId>
    <artifactId>mockito-core</artifactId>
    <version>2.16.0</version>
    <scope>test</scope>
</dependency>

Website set

Jar compresses files from the well-known HTML / CSS / JS framework. The most popular is angular, which is surprising, but maybe because it's used in Spring + Angular.

• Angular

GitHub：https://github.com/angular/angular Version information: Server-side JavaScript developed by Google

<dependency>
    <groupId>org.webjars.bower</groupId>
    <artifactId>angular</artifactId>
    <version>1.6.9</version>
</dependency>

• Jquery : JavaScript library

GitHub：https://github.com/jquery/jquery Version information: https://mvnrepository.com/artifact/org.webjars.bower/jquery

<dependency>
    <groupId>org.webjars.bower</groupId>
    <artifactId>jquery</artifactId>
    <version>3.3.1</version>
</dependency>

• Polymer : JavaScript UI framework developed by Google

GitHub：https://github.com/Polymer/polymer Version information: https://mvnrepository.com/artifact/org.webjars.bowergithub.polymer/polymer

<dependency>
    <groupId>org.webjars.bowergithub.polymer</groupId>
    <artifactId>polymer</artifactId>
    <version>2.6.0</version>
</dependency>

• Bootstrap : HTML / CSS / JS standard framework

GitHub：https://github.com/twbs/bootstrap Version information: https://mvnrepository.com/artifact/org.webjars/bootstrap

<dependency>
    <groupId>org.webjars</groupId>
    <artifactId>bootstrap</artifactId>
    <version>4.0.0-2</version>
</dependency>

utility

• Guava: Google Core Libraries for Java : A library packed with various useful functions such as character operations, collection operations, and file operations. Read as guava. The recent popularity seems to be guava> apache.commons because of its modern construction and frequent maintenance.

GitHub：https://github.com/google/guava Version information: https://mvnrepository.com/artifact/com.google.guava/guava Usage example: https://qiita.com/miyasumas/items/f5b09e8712d020cadf70

<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>23.0</version>
</dependency>

• Apache Commons : A library of useful functions similar to the above. It is older than Guava.

GitHub：https://github.com/apache/commons-lang Version information: https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 Usage example: https://qiita.com/asahina_dev/items/11ea0637f85243461c7d

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.7</version>
</dependency>

JSON operation

• Jackson : JSON operation library

Version information: https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind Usage example: https://qiita.com/nijuya_o/items/a6d692c2083726ac56b2

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.9.4</version>
</dependency>

• google-gson :Same as above. Recently, it seems that jackson> gson. I personally like this one.

GitHub：https://github.com/google/gson Version information: https://mvnrepository.com/artifact/com.google.code.gson/gson Usage example: https://qiita.com/naoi/items/6b184700b2a41fb46356

<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.8.2</version>
</dependency>

Config operation

• Apache Commons Configuration : Can read a wide variety of config files (properties, xml)

GitHub：https://github.com/apache/commons-configuration Version information: https://mvnrepository.com/artifact/org.apache.commons/commons-configuration2 Usage example: http://d.hatena.ne.jp/daisuke-m/20091022/1256215300

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-configuration2</artifactId>
    <version>2.2</version>
</dependency>

Template engine

• Apache FreeMarker : You can easily embed expressions and functions using tags that include sharps. Most popular.

GitHub：https://github.com/apache/freemarker Version information: https://mvnrepository.com/artifact/org.freemarker/freemarker Usage example: https://iwb.jp/freemarker-reference/

<dependency>
    <groupId>org.freemarker</groupId>
    <artifactId>freemarker</artifactId>
    <version>2.3.23</version>
</dependency>

• Velocity : A template engine that uses $ to use variables like PHP.

Version information: https://mvnrepository.com/artifact/org.apache.velocity/velocity Usage example: http://www.techscore.com/tech/Java/ApacheJakarta/Velocity/index/

<dependency>
    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity</artifactId>
    <version>1.7</version>
</dependency>

• Thymeleaf : A template engine that embeds EL expressions in HTML. I'm 6th in the ranking, but I personally like it the most.

GitHub：https://github.com/thymeleaf/thymeleaf Version information: https://mvnrepository.com/artifact/org.thymeleaf/thymeleaf Usage example: https://iwb.jp/freemarker-reference/

<dependency>
    <groupId>org.thymeleaf</groupId>
    <artifactId>thymeleaf</artifactId>
    <version>3.0.9.RELEASE</version>
</dependency>

Reference: Thymeleaf extension (extension that uses Java 8 Date and Time API)

Version information: https://mvnrepository.com/artifact/org.thymeleaf.extras/thymeleaf-extras-java8time

<dependency>
    <groupId>org.thymeleaf.extras</groupId>
    <artifactId>thymeleaf-extras-java8time</artifactId>
    <version>3.0.1.RELEASE</version>
</dependency>

Bean validation

• Bean Validation API : Validation function in the standard function of Java EE. You can check Null, regular expressions, phone numbers, etc.

GitHub：https://github.com/beanvalidation/beanvalidation-api Version information: https://mvnrepository.com/artifact/javax.validation/validation-api Usage example: https://qiita.com/opengl-8080/items/3926fbde5469c0b330c2

<dependency>
    <groupId>javax.validation</groupId>
    <artifactId>validation-api</artifactId>
    <version>2.0.1.Final</version>
</dependency>

• Hibernate Validator : In addition to the above, we also provide checks such as email addresses.

GitHub：https://github.com/hibernate/hibernate-validator Version information: https://mvnrepository.com/artifact/org.hibernate.validator/hibernate-validator Usage example: https://terasolunaorg.github.io/guideline/public_review/ArchitectureInDetail/Validation.html#id15

<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.0.9.Final</version>
</dependency>

HTTP client

• Apache HttpCore : Library that makes HTTP communication (GET, POST) convenient

GitHub：https://github.com/apache/httpcomponents-core Version information: https://mvnrepository.com/artifact/org.apache.httpcomponents/httpcore Usage example: https://itsakura.com/java-httpclient

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpcore</artifactId>
    <version>4.4.9</version>
</dependency>

• OkHttp : A library with the same functionality as above.

GitHub：https://github.com/square/okhttp Version information: https://mvnrepository.com/artifact/com.squareup.okhttp3/okhttp Usage example: https://qiita.com/hymmr/items/5d87277b44892e7b690b

<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp</artifactId>
    <version>3.10.0</version>
</dependency>

Input / output

• Commons IO : Library for file input / output, etc.

GitHub：https://github.com/apache/commons-io Version information: https://mvnrepository.com/artifact/commons-io/commons-io Usage example: https://qiita.com/yuji38kwmt/items/175461f99b5c1f3123b2

<dependency>
    <groupId>commons-io</groupId>
    <artifactId>commons-io</artifactId>
    <version>2.6</version>
</dependency>

XML manipulation

• Xerces : High-performance XML file manipulable library, XML manipulation seems to be more popular than dom4j.

GitHub：https://github.com/jboss/xerces Version information: https://mvnrepository.com/artifact/xerces/xercesImpl

<dependency>
    <groupId>xerces</groupId>
    <artifactId>xercesImpl</artifactId>
    <version>2.11.0</version>
</dependency>

• dom4j :Same as above. I think this one is easier to operate.

GitHub：https://github.com/dom4j/dom4j Version information: https://mvnrepository.com/artifact/dom4j/dom4j Usage example: http://brbranch.jp/blog/201503/java/dom4j/

<dependency>
    <groupId>dom4j</groupId>
    <artifactId>dom4j</artifactId>
    <version>1.6.1</version>
</dependency>

Bean operation

• Apache Commons BeanUtils : Library used when you want to get / copy Java Bean values.

GitHub：https://github.com/apache/commons-beanutils Version information: https://mvnrepository.com/artifact/commons-beanutils/commons-beanutils Usage example: https://qiita.com/horimislime/items/a9b9cf89e13cc9639ff2

<dependency>
    <groupId>commons-beanutils</groupId>
    <artifactId>commons-beanutils</artifactId>
    <version>1.9.3</version>
</dependency>

bug

-Spotbugs (formerly FindBugs) : Static bug analysis / discovery tool. Detect for bugs with annotations. The name has changed from FindBugs to Spotbugs.

GitHub：https://github.com/findbugsproject/findbugs Version information: https://mvnrepository.com/artifact/com.google.code.findbugs/jsr305 Usage example: http://spotbugs.readthedocs.io/ja/latest/eclipse.html

<dependency>
    <groupId>com.google.code.findbugs</groupId>
    <artifactId>jsr305</artifactId>
    <version>3.0.2</version>
</dependency>

ORM

• Hibernate : The most famous ORM. A library that associates objects with RDBs.

GitHub：https://github.com/hibernate/hibernate-orm Version information: https://mvnrepository.com/artifact/org.hibernate/hibernate-core Usage example: http://www.techscore.com/tech/Java/Others/Hibernate/index/

<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-core</artifactId>
    <version>5.2.16.Final</version>
</dependency>

• MyBatis : One of the characteristic ORMs that can operate DB with XML or annotation

GitHub：https://github.com/tuguangquan/mybatis Version information: https://mvnrepository.com/artifact/org.mybatis/mybatis Usage example: https://qiita.com/opengl-8080/items/a9b5d4038f19d4813ee6

<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.4.6</version>
</dependency>

• Doma : ORM made in Japan. One of the features is 2way SQL.

GitHub：https://github.com/domaframework/doma Version information: https://mvnrepository.com/artifact/org.seasar.doma/doma Usage example: http://doma.readthedocs.io/ja/stable/getting-started/

<dependency>
    <groupId>org.seasar.doma</groupId>
    <artifactId>doma</artifactId>
    <version>2.19.2</version>
</dependency>

↓ If you use it with Spring Boot, the following is more convenient.

Version information: https://mvnrepository.com/artifact/org.seasar.doma.boot/doma-spring-boot-starter

<dependency>
    <groupId>org.seasar.doma.boot</groupId>
    <artifactId>doma-spring-boot-starter</artifactId>
    <version>1.1.1</version>
</dependency>

DB driver

• MySQL : MySQL JDBC driver

GitHub：https://github.com/spullara/mysql-connector-java Version information: https://mvnrepository.com/artifact/mysql/mysql-connector-java

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>6.0.6</version>
</dependency>

• PostgreSQL : JDBC driver for PostgreSQL

Version information: https://mvnrepository.com/artifact/org.postgresql/postgresql

<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>42.2.2</version>
</dependency>

• SQL Server : SQL Server JDBC driver

Version information: https://mvnrepository.com/artifact/mysql/mysql-connector-java

<dependency>
    <groupId>com.microsoft.sqlserver</groupId>
    <artifactId>mssql-jdbc</artifactId>
    <version>6.4.0.jre9</version>
    <scope>test</scope>
</dependency>

• MongoDB : MongoDB (NoSQL) JDBC driver

Version information: https://mvnrepository.com/artifact/org.mongodb/mongo-java-driver

<dependency>
    <groupId>org.mongodb</groupId>
    <artifactId>mongo-java-driver</artifactId>
    <version>3.6.3</version>
</dependency>

Embedded SQL

• H2 : A standalone RDB that runs programmatically.

Version information: https://mvnrepository.com/artifact/com.h2database/h2

<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <version>1.4.197</version>
    <scope>test</scope>
</dependency>

• HyperSQL Database : 100% Java SQL database engine.

Version information: https://mvnrepository.com/artifact/org.hsqldb/hsqldb

<dependency>
    <groupId>org.hsqldb</groupId>
    <artifactId>hsqldb</artifactId>
    <version>2.4.0</version>
    <scope>test</scope>
</dependency>

Excel & Word operation

• Apache POI : Can operate Excel & Word

GitHub：https://github.com/apache/poi Version information: https://mvnrepository.com/artifact/org.apache.poi/poi Usage example: https://qiita.com/ptiringo/items/d8b4cc667b4ad6827939 (Word)

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>3.17</version>
</dependency>

HTML manipulation

• jsoup : Library for parsing, editing and scraping HTML files

GitHub：https://github.com/jhy/jsoup Version information: https://mvnrepository.com/artifact/org.jsoup/jsoup Usage example: https://qiita.com/opengl-8080/items/d4864bbc335d1e99a2d7

<dependency>
    <groupId>org.jsoup</groupId>
    <artifactId>jsoup</artifactId>
    <version>1.11.2</version>
</dependency>

CSV file operation

• OpenCSV : Library for manipulating CSV

GitHub：https://github.com/jlawrie/opencsv Version information: https://mvnrepository.com/artifact/com.opencsv/opencsv Usage example: https://qiita.com/buta29/items/01fa40612feeeab5063c

<dependency>
    <groupId>com.opencsv</groupId>
    <artifactId>opencsv</artifactId>
    <version>4.1</version>
</dependency>

• Apatch Commons CSV : Library with the same function as above

GitHub：https://github.com/apache/commons-csv Version information: https://mvnrepository.com/artifact/org.apache.commons/commons-csv Usage example: http://wannabe-jellyfish.hatenablog.com/entry/2017/06/05/210209

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-csv</artifactId>
    <version>1.5</version>
</dependency>

message

• Apache Kafka : Distributed messaging system. It seems to be convenient for quickly linking a large amount of data.

GitHub：https://github.com/apache/kafka Version information: https://mvnrepository.com/artifact/org.apache.kafka/kafka Usage example: https://qiita.com/FJKei/items/3c8f5c6ab605b781aae5

<dependency>
    <groupId>org.apache.kafka</groupId>
    <artifactId>kafka_2.12</artifactId>
    <version>1.0.1</version>
</dependency>

• Apache ActiveMQ : Same message system as above.

GitHub：https://github.com/apache/activemq Version information: https://mvnrepository.com/artifact/org.apache.activemq/activemq-core

<dependency>
    <groupId>org.apache.activemq</groupId>
    <artifactId>activemq-core</artifactId>
    <version>5.7.0</version>
</dependency>

actor

• Akka : A library that makes parallel processing convenient. I have never used it.

GitHub：https://github.com/akka/akka Version information: https://mvnrepository.com/artifact/com.typesafe.akka/akka-actor

<dependency>
    <groupId>com.typesafe.akka</groupId>
    <artifactId>akka-actor_2.12</artifactId>
    <version>2.5.11</version>
</dependency>

PDF operation

• Apache PDFBox : Manipulate PDF files. The most popular PDF library

GitHub：https://github.com/apache/pdfbox Version information: https://mvnrepository.com/artifact/org.apache.pdfbox/pdfbox Usage example: https://qiita.com/EichiSanden/items/8f142782f0b3f997b377

<dependency>
    <groupId>org.apache.pdfbox</groupId>
    <artifactId>pdfbox</artifactId>
    <version>2.0.9</version>
</dependency>

• iText PDF : A library of PDF file operations along with PDFBox. Easy to use, but be careful of the license when handling.

GitHub：https://github.com/itext/itextpdf Version information: https://mvnrepository.com/artifact/com.itextpdf/itextpdf

<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itextpdf</artifactId>
    <version>5.5.13</version>
</dependency>

send e-mail

• JavaMail : Standard function of Java EE. JavaMail for sending emails

GitHub：https://github.com/itext/itextpdf Version information: https://github.com/javaee/javamail

<dependency>
    <groupId>javax.mail</groupId>
    <artifactId>javax.mail-api</artifactId>
    <version>1.6.1</version>
</dependency>

Task schedule

• Quartz : Jobs can be executed at a specified time. If you use Spring personally, I think Spring Batch is fine.

GitHub：https://github.com/quartz-scheduler/quartz Version information: https://mvnrepository.com/artifact/org.quartz-scheduler/quartz Usage example: https://qiita.com/kojisaiki/items/e338458f8e19a003354e

<dependency>
    <groupId>org.quartz-scheduler</groupId>
    <artifactId>quartz</artifactId>
    <version>2.3.0</version>
</dependency>

file upload

• Apache Commons FileUpload : Can manipulate the data of POSTed files

GitHub：https://github.com/apache/commons-fileupload Version information: https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload Usage example: https://www.javadrive.jp/servlet/fileupload_tutorial/index5.html

<dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.3.3</version>
</dependency>

Compression / decompression

• Apache Commons Compress : Easy to compress and decompress. It also supports a wide variety of formats (zip, tar, jar, 7z)

GitHub：https://github.com/apache/commons-compress Version information: https://mvnrepository.com/artifact/org.apache.commons/commons-compress Usage example: http://grachro.hatenablog.com/entry/20100405/1270477346

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-compress</artifactId>
    <version>1.16.1</version>
</dependency>

Social network client

• Twitter4J : Used when acquiring / posting Twitter information

GitHub：https://github.com/yusuke/twitter4j Version information: https://mvnrepository.com/artifact/org.twitter4j/twitter4j-core Usage example: http://kikutaro777.hatenablog.com/entry/2013/07/19/195626

<dependency>
    <groupId>org.twitter4j</groupId>
    <artifactId>twitter4j-core</artifactId>
    <version>4.0.6</version>
</dependency>

Other

• Lombok : How to read (Lombok) or (Lombok). A library that allows you to say goodbye to troublesome descriptions such as Setter / Getter

GitHub：https://github.com/rzwitserloot/lombok Version information: https://mvnrepository.com/artifact/org.projectlombok/lombok Usage example: https://qiita.com/opengl-8080/items/671ffd4bf84fe5e32557

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.16.20</version>
    <scope>provided</scope>
</dependency>

• Flyway : DB version control library

GitHub：https://github.com/flyway Version information: https://mvnrepository.com/artifact/org.flywaydb/flyway-core Usage example: https://qiita.com/opengl-8080/items/6368c19a06521b65a655

<dependency>
    <groupId>org.flywaydb</groupId>
    <artifactId>flyway-core</artifactId>
    <version>5.0.7</version>
</dependency>

• Swagger : API documentation library

You can add items endlessly in JSON format, but if you define it properly, it will document it.

GitHub：https://github.com/swagger-api/swagger-core Version information: https://mvnrepository.com/artifact/io.swagger.core.v3/swagger-core 　　　　　　　　https://mvnrepository.com/artifact/io.swagger.core.v3/swagger-jaxrs2 Usage example: https://qiita.com/sato_gohan/items/3df6feb628d559dc5fda

<dependency>
    <groupId>io.swagger.core.v3</groupId>
    <artifactId>swagger-core</artifactId>
    <version>2.0.0-rc4</version>
</dependency>
<dependency>
     <groupId>io.swagger.core.v3</groupId>
     <artifactId>swagger-jaxrs2-servlet-initializer</artifactId>
     <version>2.0.0</version>
</dependency>