Meja spreadsheet library

Meja is a library for handling tabular data such as Excel-Sheets, CSV-data etc.

Name

As it's rather common to give everything Java related a name of indo/malay origin, I chose 'meja' which is the indonesian word for table (as in furniture).

Using Meja in your projects

• The Minimal Java version for the upcoming version 8.x is be Java 21.
• The Java 17 compatible version 7.x will be maintained until the next LTS Java version (Java 25) is released. Note that Java 21/JavaFX 21 is already needed in version 7.x for all JavaFX related modules.

Meja is available in the Maven central repository.

You need at least the following modules:

• meja: core functionality, CSV import and export, HTML export
• meja-generic: generic implementation (memory efficient)

Add any combination of the following as needed:

• meja-poi: Apache POI based implementation (supports Excel XLSX and XLS file format)
• meja-db: for reading data directly from JDBC result sets
• meja-swing: for displaying sheets and workbooks in Swing applications
• meja-fx: for displaying sheets and workbooks in JavaFX applications

Maven

    <dependency>
        <groupId>com.dua3.meja</groupId>
        <artifactId>[meja_module]</artifactId>
        <version>[meja_version]</version>
    </dependency>

Gradle (Groovy DSL)

    implementation 'com.dua3.meja:[meja_module]:[meja_version]'

Gradle (Kotlin DSL)

    implementation("com.dua3.meja:[meja_module]:[meja_version]")

Building

Java 21 is required for building Meja.

Clone the repository and run ./gradlew build to build the library, ./gradlew publishToMavenLocal to publish to your local Maven repository.

License

Meja is released under the Apache License 2.0.

Modules

Meja consists of different modules, each providing different functionality.

Module: com.dua3.meja

This is the base module providing functionality shared by different models.

Module: com.dua3.meja.generic

A generic Workbook implementation. Fast and memory efficient. Use this implementation when creating workbooks in memory. Also defines the CSV FileType.

com.dua3.meja.poi

An implementation backed by the Apache POI implementation of the Microsoft Office Excel file format. Defines FileTypes for xls and xlsx files. Use this implementation to read and modify Excel files.

com.dua3.meja.swing

Defines Swing controls for displaying Sheets and Workbooks.

com.dua3.meja.samples

Several small samples to demonstrate how to use this library.

com.dua3.meja.fx

Utilities for JavaFX.

Logging

Meja uses Log4J2-API as logging facade, the same as the Apache POI library that is used for reading and writing Excel files.

Handling of null parameters and return values

Meja uses Cabe to ensure correct handling of null values.

This means that:

• Only parameters marked as @Nullable accept null values. When null is passed for a parameter not marked as @Nullable, an IllegalArgumentException is thrown. The name of the offending parameter is given in the exception message.

• Only methods where the return value is marked as @Nullable will ever return null.