Java API to Automate Documents & Reports

Build Document Automation Applications to Fetch Data; put it in Customizable Templates & Generate Dynamic Reports via Java API.

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Java document generation API

GroupDocs.Assembly for Java


GroupDocs.Assembly for Java API helps you rapidly develop document automation and reporting applications in Java to generate custom reports from templates without installing any external software. The report generation engine fetches data from the template document, assembles it and generates reports in the specified output format according to the defined syntax. It allows you to configure and insert formatting properties of template elements dynamically and supports various data sources (JSON, XML, OData, databases, spreadsheet as table of data, word processing table as table of data and databases) to retrieve data from.

The document assembly library recognizes multiple document formats and allows you to create templates in all supported file types such as PDF, HTML, Outlook email, Microsoft Office Word, Excel worksheets, PowerPoint presentations and text. It supports LINQ-based template syntax and users can also configure and insert formatting properties of template elements dynamically.

GroupDocs.Assembly for Java is easy to integrate with new or existing java applications. It is highly compatible with all Java versions and supports popular operating systems (Windows, Linux, MacOS) that are capable to run Java runtime.

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GroupDocs.Assembly for Java Features



Multiple Data Formats Support


Use Formulae & Perform Sequential Data Operations


Apply Upper, Lower, Capital, FirstCap Formatting to Strings in Template Syntax


Template Syntax support Formatting of Ordinal, Cardinal, Alphabetic Numeric Nature


Support Template Documents with Custom Variables & Text Comments within Template Syntax Tags


Dynamically Insert Out Document Content in Report


Dynamically Configure Background Color of HTML Documents & Generate Barcode in Reports


Dynamically Insert Hyperlinks in Reports & Apply Attributes to Email Message Body


Dynamically Attach Email Attachments


Support of NEXT Field Analogue of Microsoft Word


Update Fields during Word Processing Document Assembly


Apply Formula during Spreadsheet Assembly


Template Formatting for Numeric, Text, Image, Date-Time, Chart Elements


Conditional Formatting of Template Text Elements


LINQ-Based Template Syntax


Change Format of Assembled File using Explicit Specifications or File Extension


Auto-Removal of Empty Paragraphs


Generate Various Report Types, e.g., Charts, Image, Tables, Lists and more


Inline Template Syntax Errors in Generated Documents instead of Exception Throwing


Load Template Documents from HTML with Resources and Save Assembled Word, Excel, PowerPoint & Emails to HTML with Resources


Dynamically Restart A Numbered List in Word Documents as well as Emails with HTML & RTF Bodies

Manipulate Template Elements

Manipulate numerous template elements with GroupDocs.Assembly for Java API. The template elements that you can work with include, text blocks, Images, Hyperlinks, HTML blocks, Barcodes (via Barcode fonts), and Charts. You can also apply repeated blocks & conditional blocks for list items and table rows. Dynamic merging of table cells holding the same text, based on template expressions for documents, presentations, spreadsheets, and emails with HTML and RTF bodies.

Manipulate List Reports

Using GroupDocs.Assembly for Java API, supports following types of List Reports:

  • Bulleted List
  • Numbered List
  • Colored Numbered List

Manipulate Chart Reports

GroupDocs.Assembly for Java supports following type of Chart Reports:

  • Bubble Chart, which displays three dimensions of data
  • Column Chart
  • Pie Chart
  • Scatter Chart
  • Series Chart (Colored)

Manipulate Table Reports

GroupDocs.Assembly for Java supports following types of Table Reports:

  • Master-Detail Table
  • Table with Highlighted Rows
  • Table with Alternate Content
  • Table with Filtering, Grouping, and Ordering

You can also use Data Bands in table rows.

Easily Integrate

Integration of GroupDocs.Assembly for Java API with your Java application is like a breeze. What follows is an example block of code that generates report in OpenDocument format using Java:

Insert nested external documents in word document - Java

// Instantiate DocumentAssembler class
DocumentAssembler assembler = new DocumentAssembler();
//Call AssembleDocument to generate report
assembler.assembleDocument("D:\\WordTemplates\\Nested External Document.docx", "D:\\WordReports\\Nested External Document.docx", 
new DataSourceInfo( new DataStorage(), null));
//(See new DataStorage() method details at

Support and Learning Resources


GroupDocs.Assembly offers document automation APIs for other popular development environments as listed below: