Add or Modify VBA Macro in Excel using Java | https://blog.aspose.com/2021/06/08/add-modify-vba-macros-in-excel-using-java/

add-vba-macro.java

// For complete examples and data files, please go to https://github.com/aspose-cells/Aspose.Cells-for-Java
// Load Excel workbook
Workbook workbook = new Workbook("workbook.xlsm");

// Access first worksheet
Worksheet worksheet = workbook.getWorksheets().get(0);

// Add VBA Module
int idx = workbook.getVbaProject().getModules().add(worksheet);

// Access the VBA Module, set its name and codes
VbaModule module = workbook.getVbaProject().getModules().get(idx);
module.setName("TestModule");
module.setCodes("Sub ShowMessage()" + "\r\n" + "    MsgBox \"Welcome to Aspose!\"" + "\r\n" + "End Sub");

// Save the workbook
workbook.save("output.xlsm", SaveFormat.XLSM);

modify-vba-macro.java

// For complete examples and data files, please go to https://github.com/aspose-cells/Aspose.Cells-for-Java
// Create workbook object from source Excel file
Workbook workbook = new Workbook("sample.xlsm");

// Change the VBA Module Code
VbaModuleCollection modules = workbook.getVbaProject().getModules();

for (int i = 0; i < modules.getCount(); i++) {
	VbaModule module = modules.get(i);
	String code = module.getCodes();

	// Replace the original message with the modified message
	if (code.contains("This is test message.")) {
		code = code.replace("This is test message.", "This is Aspose.Cells message.");
		module.setCodes(code);
	}
}

// Save the output Excel file
workbook.save("output.xlsm");

Read the complete article: https://blog.aspose.com/2021/06/08/add-modify-vba-macros-in-excel-using-java/