A sample way to define a Retrofit interface for multiple required and optional request arguments

AllArgumentCombinations.java

public interface MyApiService {
    
    public Call<String> method(String requiredArgument1);
    
    public Call<String> method(String requiredArgument1, String optionalArgument1);
    
    public Call<String> method(String requiredArgument1, String optionalArgument1, String optionalArgument2);
    
    //Add every possible combination of arguments
}