You can create an AEM application by using the Java Eclipse Integrated Development Environment (IDE). By building an AEM application using Eclipse, you can access features within the IDE such as code completion and the ability to remote debug the application. That is, you can set a breakpoint on a line of Java code used for an OSGi bundle and you can walk through the code to troubleshoot issues.
You can synchronize code (both Java code and JSP code) in Eclipse with the code in the AEM JCR. For example, assume that you have application logic in Eclipse that represents a JSP component. You can synchronize the code in Eclipse with code in the AEM JCR using the vault tool. That is, you can check in code you write in Eclipse into the AEM JCR. Likewise, if you make a change in AEM using CRXDE lite, you can checkout the code that results in the code in Eclipse being updated. To synchronize code, you configure the vault tool (this is shown later in this development article).
The following illustration shows application logic for an AEM application within Eclipse.
To read this development article, click https://helpx.adobe.com/experience-manager/using/creating-aem-project-using-eclipse.html.