Consider to use interface and delegation in generated Java Service interface

[mikir]

Currently, the generated Java Service interface for server forces users to use inheritance to implement protected methods:

public final class SimpleService
{
    public static abstract class SimpleServiceService implements zserio.runtime.service.ServiceInterface
    {
        public SimpleServiceService()
        {
            ...
        }

        @Override
        public byte[] callMethod(java.lang.String methodName, byte[] requestData, java.lang.Object context)
                throws zserio.runtime.ZserioError
        {
            ...
        }

        public static java.lang.String serviceFullName()
        {
            return SERVICE_FULL_NAME;
        }

        public static java.lang.String[] methodNames()
        {
            return new java.lang.String[]
            {
                "powerOfTwo"
            };
        }

        protected abstract service_types.simple_service.Response powerOfTwoImpl(
                service_types.simple_service.Request request, java.lang.Object context);

        private byte[] powerOfTwoMethod(byte[] requestData, java.lang.Object context)
                throws zserio.runtime.ZserioError
        {
            ...
        }
    ...

Consider to use interface and delegation instead of that. Then, user can provide an implementation of interface in SimpleServiceService constructor instead of inheritance and implementation of protected methods.

[mikir]

Please note that if we decide to change Java Service interface in the suggested way, we should change similarly generated C++ and Python Service interface.