Why Does My Java Project Give the Error "Selection Does Not Contain a Main Type"?

Troubleshooting "Error: Selection Does Not Contain a Main Type"

When attempting to run Java files in a new project, you may encounter the perplexing error message "Selection does not contain a main type." This error indicates that the project lacks a class with a public static void main(String[] args) method, which serves as the program's entry point. To resolve this issue, follow these steps:

1. Locate the Main Class: Identify the Java file containing the main method. In a well-organized project, this file should typically be named Main.java or something similar.
2. Add to Build Path: Right-click on the folder where the main class is located and select "Build Path" from the context menu. Choose "Use as Source Folder" to add the folder to the project's source path.
3. Run Java Application: With the main class now recognized by the compiler, right-click on the main class and select "Run As" from the context menu. Choose "Java Application" to execute the program.

Fallback Solution:

If the "Use as Source Folder" option is unavailable, navigate to the "Build Path" menu and select "Remove from Build Path" for the corresponding folder. This will enable the "Use as Source Folder" option to appear.

Once these steps are completed, the Java program should run successfully without the "Selection does not contain a main type" error.

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