generic is just casting.

JavaReturnTypeInfer.java

import java.lang.reflect.Type;

import com.fasterxml.jackson.core.type.TypeReference;

public class JavaReturnTypeInfer{
    private static String speficicType() throws Exception{
        TypeReference<String> tr = new TypeReference<String>(){};
        Type type = tr.getType();
        System.out.println(type.getTypeName()); // => java.lang.String
        return (String) Class.forName(type.getTypeName()).newInstance();
    }

    @SuppressWarnings("unchecked")
    private static <T> T inferReturnType() throws Exception{
        TypeReference<T> tr = new TypeReference<T>(){};
        Type type = tr.getType();
        System.out.println(type.getTypeName()); // => T
        return (T) Class.forName(type.getTypeName()).newInstance(); // java.lang.ClassNotFoundException: T
    }

    public static void main(String[] args) throws Exception{
        speficicType();
        String s = inferReturnType();
    }
}