This error usually means the program (Programming Project.exe) is still running or is open in the background. Because of that, the compiler can't replace or update the file.

Simple Fixes:

1. Close the running program if it's still open.

2. Restart Eclipse IDE – this helps if the program is stuck in memory.

3. Clean and build the project again – go to Project > Clean.

4. Run Eclipse as Administrator – this avoids permission issues.

After doing this, try building again. It should work.