Maven clean erase my code?

Context: To customise an appian-plugin, I use Java as the primary language.

I have added codes into a class that belongs to the plugin working space, and anytime I run maven clean install, my codes will be removed throughout the clean process. According to my colleagues, it might be due to a.wsdl file that produces files automatically when it is redeployed. Please advise. Thank you very much.

This is the code fragment I'm attempting to put.

public static Comparator  sortWageIncrementFinancialYr = new Comparator () {
        public int compare(DummyFormData u1, DummyFormData u2) {
            int compare1 = u1.financialYr.get(0);
            int compare2 = u2.financialYr.get(0);
            
            Boolean result = compare1 > compare2;
            return result  ? 1 : -1;
        }
        
    };

.wsdl codes associated with this