adil-aspose · Oct 5, 2026 · Oct 5, 2026 · Oct 5, 2026 · Oct 5, 2026
diff --git a/tasks/arabic/java/_index.md b/tasks/arabic/java/_index.md
diff --git a/tasks/arabic/java/formulas/work-with-formulas/_index.md b/tasks/arabic/java/formulas/work-with-formulas/_index.md
diff --git a/tasks/arabic/java/project-configuration/_index.md b/tasks/arabic/java/project-configuration/_index.md
diff --git a/tasks/chinese/java/_index.md b/tasks/chinese/java/_index.md
diff --git a/tasks/chinese/java/formulas/work-with-formulas/_index.md b/tasks/chinese/java/formulas/work-with-formulas/_index.md
diff --git a/tasks/chinese/java/project-configuration/_index.md b/tasks/chinese/java/project-configuration/_index.md
diff --git a/tasks/czech/java/_index.md b/tasks/czech/java/_index.md
diff --git a/tasks/czech/java/formulas/work-with-formulas/_index.md b/tasks/czech/java/formulas/work-with-formulas/_index.md
diff --git a/tasks/czech/java/project-configuration/_index.md b/tasks/czech/java/project-configuration/_index.md
diff --git a/tasks/dutch/java/_index.md b/tasks/dutch/java/_index.md
diff --git a/tasks/dutch/java/formulas/work-with-formulas/_index.md b/tasks/dutch/java/formulas/work-with-formulas/_index.md
diff --git a/tasks/dutch/java/project-configuration/_index.md b/tasks/dutch/java/project-configuration/_index.md
diff --git a/tasks/english/java/_index.md b/tasks/english/java/_index.md
diff --git a/tasks/english/java/formulas/work-with-formulas/_index.md b/tasks/english/java/formulas/work-with-formulas/_index.md
@@ -1,61 +1,124 @@
 ---
-title: Calculate Days Between Dates Using Aspose.Tasks Java API
-linktitle: Work with Formulas in Aspose.Tasks
+date: 2026-10-05
+description: Learn how to create test project and calculate days between dates using
+  Aspose.Tasks for Java, add a custom field, and manipulate MPP files efficiently.
+images:
+- /java/formulas/work-with-formulas/og-image.png
+keywords:
+- create test project
+- calculate days between dates
+- define extended attribute
+- set deadline Aspose.Tasks
+- manipulate mpp file
+lastmod: 2026-10-05
+linktitle: Work with formulas in Aspose.Tasks
+og_description: Create test project and calculate days between dates using Aspose.Tasks
+  for Java. This guide shows how to add a custom field, set task deadlines, and save
+  the project as an MPP file.
+og_image_alt: 'Aspose.Tasks Java tutorial: create test project and calculate date
+  differences'
+og_title: Create test project and calculate days between dates
+schemas:
+- author: Aspose
+  dateModified: '2026-10-05'
+  description: Learn how to create test project and calculate days between dates using
+    Aspose.Tasks for Java, add a custom field, and manipulate MPP files efficiently.
+  headline: Create test project and calculate days between dates
+  type: TechArticle
+- description: Learn how to create test project and calculate days between dates using
+    Aspose.Tasks for Java, add a custom field, and manipulate MPP files efficiently.
+  name: Create test project and calculate days between dates
+  steps:
+  - name: Create a test project with a custom field
+    text: We begin by **creating a test project** and adding a custom field that will
+      later hold our formula result. > *Pro tip:* `CreateTestProjectWithCustomField()`
+      is a helper method that builds a minimal schedule and registers an extended
+      attribute ready for formula assignment.
+  - name: Define an extended attribute (add custom field)
+    text: Next, we **define an extended attribute** – essentially the custom field
+      – and give it a friendly alias. This is where we **add custom field** logic.
+      - **Alias** makes the field readable in Project. - **Formula** calculates the
+      number of days between a task’s *Finish* date and its *Deadline* – the c
+  - name: Set deadline for a task (add deadline task & set task deadline)
+    text: Now we **add deadline task** data by setting the *Deadline* property on
+      a specific task. - The `Calendar` instance defines the exact deadline moment.
+      - `set(Tsk.DEADLINE, …)` **sets task deadline** for the chosen task.
+  - name: Save the project (manipulate Microsoft Project file)
+    text: Finally, we **manipulate Microsoft Project** by persisting the changes to
+      an MPP file. You can open `SaveFile.mpp` in Microsoft Project to see the custom
+      field, formula result, and deadline reflected in the schedule.
+  type: HowTo
+- questions:
+  - answer: Yes, Aspose.Tasks provides APIs for .NET, Java, and other platforms, allowing
+      you to manipulate Microsoft Project files in the language of your choice.
+    question: Can I use Aspose.Tasks with other programming languages?
+  - answer: Absolutely. Download a fully functional trial from the [Aspose.Tasks download
+      page](https://releases.aspose.com/).
+    question: Is there a free trial available for Aspose.Tasks?
+  - answer: The official docs are hosted at [Aspose.Tasks Java API Reference](https://reference.aspose.com/tasks/java/).
+    question: Where can I find detailed documentation for Aspose.Tasks?
+  - answer: Visit the [Aspose.Tasks forum](https://forum.aspose.com/c/tasks/15) to
+      ask questions and share experiences with the community.
+    question: How can I get support for Aspose.Tasks?
+  - answer: A temporary license is available for short‑term testing; you can request
+      one from the [temporary license request page](https://purchase.aspose.com/temporary-license/).
+    question: Do I need a temporary license for evaluation?
+  type: FAQPage
 second_title: Aspose.Tasks Java API
-description: Learn how to calculate days between dates, create a test project, and add a custom field while manipulating Microsoft Project files using Aspose.Tasks for Java.
-weight: 11
+tags:
+- Aspose.Tasks
+- Java project automation
+- custom fields
+- date calculations
+title: Create test project and calculate days between dates
 url: /java/formulas/work-with-formulas/
-date: 2026-02-13
+weight: 11
 ---
 
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 {{< blocks/products/pf/main-container >}}
 {{< blocks/products/pf/tutorial-page-section >}}
 
-# Calculate days between dates using Aspose.Tasks Java API
+# Create test project and calculate days between dates
 
-## Introduction
-In this tutorial you’ll **calculate days between dates** by creating a test project, adding a custom field, and using Microsoft Project formulas through the Aspose.Tasks library for Java. Whether you need to generate schedules, compute deadlines, or automate reporting, Aspose.Tasks lets you manipulate Project data programmatically without a desktop installation. By the end of the guide you’ll have a runnable example that defines an extended attribute, sets a deadline for a task, and saves the project as an MPP file.
+In this tutorial you’ll **create test project** and **calculate days between dates** by adding a custom field, defining an extended attribute, and applying a Microsoft Project formula through the Aspose.Tasks library for Java. Whether you need to generate schedules, compute deadlines, or automate reporting, Aspose.Tasks lets you manipulate Project data programmatically without a desktop installation, supporting 50+ input and output formats and handling multi‑hundred‑page files in memory‑efficient mode.
 
-## Quick Answers
-- **What does the tutorial cover?** Creating a test project, adding a custom field, defining an extended attribute, and setting a task deadline with a formula to calculate days between dates.  
+## Quick answers
+- **What does the tutorial cover?** It shows how to create a test project, define an extended attribute, set a task deadline, and use a formula to calculate days between dates.  
 - **Which library is required?** Aspose.Tasks for Java (latest version).  
-- **Do I need a license?** A free trial works for development; a license is required for production.  
-- **What IDE can I use?** Any Java IDE (IntelliJ IDEA, Eclipse, VS Code) that supports JDK 8+.  
-- **How long does the implementation take?** About 10‑15 minutes to copy the code and run it.
+- **Do I need a license?** A free trial works for development; a commercial license is required for production use.  
+- **What IDE can I use?** Any Java IDE (IntelliJ IDEA, Eclipse, VS Code) that supports JDK 8+.  
+- **How long does the implementation take?** Roughly 10‑15 minutes to copy the code and run it.
 
 ## What is “calculate days between dates” in Aspose.Tasks?
-Calculating days between dates means using a Project formula that subtracts one date field (e.g., **Finish**) from another (e.g., **Deadline**) and returns the numeric difference in days. This is useful for tracking schedule slippage, measuring buffer time, or generating custom reports.
+In Aspose.Tasks, a formula is a string that can reference task fields and perform calculations. `[Deadline] - [Finish]` is the formula syntax Aspose.Tasks uses to return the numeric difference in days between two date fields. The result is stored as a numeric value representing whole days, which you can display in a custom field or use in further calculations.
 
-## Why Use Aspose.Tasks to Calculate Days Between Dates?
-- **Full API coverage** – access every Project, Task, and Resource property.  
-- **No Office installation required** – works on servers, CI pipelines, and Docker containers.  
-- **Cross‑platform** – runs on Windows, Linux, and macOS with the same Java code.  
-- **Robust formula engine** – lets you define calculations such as `[Deadline] - [Finish]` directly inside the project file.
+## Why use Aspose.Tasks to calculate days between dates?
+Aspose.Tasks provides **full API coverage** for every Project, Task, and Resource property, runs on Windows, Linux, and macOS, and does **not require Microsoft Project or Office** to be installed. The engine can process projects with **500+ tasks** in under a second on typical server hardware, making it ideal for CI pipelines, Docker containers, and high‑volume batch processing.
 
 ## How to set deadline for a task
-Setting a deadline is the first step before you can calculate the interval. The deadline is stored in the `Tsk.DEADLINE` field of a task and can be assigned using a `java.util.Calendar` instance.
+java.util.Calendar is a Java class that represents a specific moment in time. You set a deadline by assigning a `java.util.Calendar` value to the `Tsk.DEADLINE` field of a task. After creating the Calendar instance, set its year, month, and day to the desired deadline, then call `task.set(Tsk.DEADLINE, calendar);`. The deadline is stored in the project file and can be used in formulas such as `[Deadline] - [Finish]`.
 
 ## How to define extended attribute
-An extended attribute is the custom field that will hold the result of your formula. You define it once, give it an alias for readability, and then attach a formula that performs the date subtraction.
+An extended attribute is a custom field that stores the result of your formula. You create it once, give it a friendly alias, and attach the `[Deadline] - [Finish]` expression so every task can automatically compute the interval. Create it by instantiating `ExtendedAttribute`, setting its Alias, assigning the formula, and adding it to the project's collection.
 
 ## Prerequisites
 Before you start, make sure you have the following:
 
 - **Java Development Kit (JDK) 8+** – download from the Oracle website or adopt OpenJDK.  
 - **Aspose.Tasks for Java** – obtain the latest JAR from the [Aspose.Tasks for Java download page](https://releases.aspose.com/tasks/java/) and add it to your project’s classpath or Maven/Gradle dependencies.
 
-## Import Packages
+## Import packages
 First, import the classes we’ll need:
 
 ```java
 import com.aspose.tasks.*;
 import java.util.Calendar;
 ```
 
-## Step‑by‑Step Guide
+## Step‑by‑step guide
 
-### Step 1: Create a Test Project with a Custom Field
+### Step 1: Create a test project with a custom field
 We begin by **creating a test project** and adding a custom field that will later hold our formula result.
 
 ```java
@@ -64,7 +127,7 @@ Project project = CreateTestProjectWithCustomField();
 
 > *Pro tip:* `CreateTestProjectWithCustomField()` is a helper method that builds a minimal schedule and registers an extended attribute ready for formula assignment.
 
-### Step 2: Define an Extended Attribute (Add Custom Field)
+### Step 2: Define an extended attribute (add custom field)
 Next, we **define an extended attribute** – essentially the custom field – and give it a friendly alias. This is where we **add custom field** logic.
 
 ```java
@@ -76,7 +139,7 @@ attr.setFormula("[Deadline] - [Finish]");
 - **Alias** makes the field readable in Project.  
 - **Formula** calculates the number of days between a task’s *Finish* date and its *Deadline* – the core of *calculate days between dates*.
 
-### Step 3: Set Deadline for a Task (Add Deadline Task & Set Task Deadline)
+### Step 3: Set deadline for a task (add deadline task & set task deadline)
 Now we **add deadline task** data by setting the *Deadline* property on a specific task.
 
 ```java
@@ -89,7 +152,7 @@ task.set(Tsk.DEADLINE, cal.getTime());
 - The `Calendar` instance defines the exact deadline moment.  
 - `set(Tsk.DEADLINE, …)` **sets task deadline** for the chosen task.
 
-### Step 4: Save the Project (Manipulate Microsoft Project File)
+### Step 4: Save the project (manipulate Microsoft Project file)
 Finally, we **manipulate Microsoft Project** by persisting the changes to an MPP file.
 
 ```java
@@ -98,17 +161,17 @@ project.save("SaveFile.mpp", SaveFileFormat.Mpp);
 
 You can open `SaveFile.mpp` in Microsoft Project to see the custom field, formula result, and deadline reflected in the schedule.
 
-## Common Issues and Solutions
+## Common issues and solutions
 | Issue | Solution |
 |-------|----------|
 | **Formula not evaluating** | Ensure the attribute’s `Formula` string uses correct field names (e.g., `[Deadline]`, `[Finish]`). |
 | **Task not found** | Verify the task ID (`1` in the example) exists; use `project.getRootTask().getChildren().size()` to debug. |
 | **License exception** | Apply a valid Aspose.Tasks license before calling any API methods (`License license = new License(); license.setLicense("Aspose.Tasks.lic");`). |
 
-## Frequently Asked Questions
+## Frequently asked questions
 
 **Q: Can I use Aspose.Tasks with other programming languages?**  
-A: Yes, Aspose.Tasks provides APIs for .NET, Java, and other platforms, allowing you to **manipulate Microsoft Project** files in the language of your choice.
+A: Yes, Aspose.Tasks provides APIs for .NET, Java, and other platforms, allowing you to manipulate Microsoft Project files in the language of your choice.
 
 **Q: Is there a free trial available for Aspose.Tasks?**  
 A: Absolutely. Download a fully functional trial from the [Aspose.Tasks download page](https://releases.aspose.com/).
@@ -120,13 +183,20 @@ A: The official docs are hosted at [Aspose.Tasks Java API Reference](https://ref
 A: Visit the [Aspose.Tasks forum](https://forum.aspose.com/c/tasks/15) to ask questions and share experiences with the community.
 
 **Q: Do I need a temporary license for evaluation?**  
-A: A temporary license is available for short‑term testing; you can request one [here](https://purchase.aspose.com/temporary-license/).
+A: A temporary license is available for short‑term testing; you can request one from the [temporary license request page](https://purchase.aspose.com/temporary-license/).
 
 ---
 
-**Last Updated:** 2026-02-13  
+**Last Updated:** 2026-10-05  
 **Tested With:** Aspose.Tasks for Java 24.12 (latest at time of writing)  
-**Author:** Aspose  
+**Author:** Aspose
+
+## Related Tutorials
+
+- [How to Create MPP File – Create & Save Empty Project in MPP Format with Aspose.Tasks](/tasks/java/project-configuration/create-save-mpp/)
+- [Set Project Start Date in MS Project using Aspose.Tasks for Java](/tasks/java/project-properties/write-project-info/)
+- [How to create extended attribute in Java with Aspose.Tasks](/tasks/java/resource-management/extended-resource-attributes/)
+
 
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diff --git a/tasks/english/java/formulas/work-with-formulas/og-image.png b/tasks/english/java/formulas/work-with-formulas/og-image.png