How to find out "separation of anxiety" in java

Question

In another question, someone told me to implement the following in my java program. But I am very new to Java, and I don’t know how to start converting my simple program into this structure:

Data Access Layer (read/write data)
Service Layer (isolated business logic)
Controller (Link between view and model)
Presentation (UI)
dependency injection. 
program to the interface:

Does this fall within the scope? Should I start Spring training and will this structure evolve naturally? Or can I implement the above technologies one by one without using a framework?

Answer 1

You can implement them without a framework if you want, but you are giving up any advantages that the infrastructure offers you.

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package model;

/**
 * A model object that interesting from your problem point of view
 */
public class Foo
{
}

package persistence;

/**
 * CRUD operations for a Foo 
 */
public interface FooDao
{
    Foo find(Long id);
    List<Foo> find();
    void saveOrUpdate(Foo foo);
    void delete(Foo foo);
}


package service;

/**
 * Just a data service that wraps FooDao for now, but other use cases would 
 * mean other methods.  The service would also own the data connection and manage 
 * transactions.
 */
public interface FooService
{
    Foo find(Long id);
    List<Foo> find();
    void saveOrUpdate(Foo foo);
    void delete(Foo foo);
}

package view;

/**
 * A class that owns services, validates and binds input from UI, and handles routing 
 * to the next view once service is complete.
 */
public interface FooController
{
   ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response);    
}

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Answer 2

, Domain Driven Design. Java. , , , .

Answer 3

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Answer 4

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Answer 5

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Answer 6

, calss .

Data Access Layer (read/write data) -> one class for presisting laoding
Service Layer (isolated business logic) -> one calss with bussiness logic
Controller (Link between view and model) -> in simple swing app this merges with UI
Presentation (UI) -> one class for one widnow
dependency injection -> not used in small apps 
program to the interface -> Your service class should use interface tah is used by other class instead of directly your serivce implementation:

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- ! , begginigs!