====== Java ======



===== Basic =====
  * 기본 연산, 제어 구조
  * 산술 연산, 논리 연산
  * 자료형; 기본자료형, 참조형, 인스턴스, 래퍼클래스, 상수
  * 비교 연산; 주요 비교 연산자, 참조형 비교, String 비교, 자료형 비교(instanceof 연산자), 논리 연산
  * 조건 분기; if, switch, for, while, do-while, break, continue, return
  * 객체지향
    * 캡슐화
    * 상속
    * 생성자
    * 다형성
    * 인터페이스
    * 위임
  * 제네릭
  * 람다식

===== Preparing =====
  * 개발환경 구성
    * JDK
    * IDE 혹은 TextEditor
    * Build 도구 (Maven, Gradle) 및 의존성관리
    * 기타 개발 도구


===== Examples =====
  * ''String'' -> ''StringBuilder''

  * ''java.util.Date'' <-> ''java.time.Instant''
  * ''java.util.Calendar'' -> ''java.time.Instant''
  * ''java.text.SimpleDateFormat''
  * ''java.time''
    * Local
    * Zoned
    * Offset
  * Collections
    * List; ArrayList, LinkedList
    * Set; HashSet, LinkedHashSet
    * Map; HashMap, LinkedHashMap
    * 


  * 람다식

  (자료형 인수, ...) -> { ... 임의의 처리 ...}

==== Database ====
<sxh java>
import java.sql.*;

...
...
  Connection conn = null;
  
  try
  {
    Class.forName("DRIVER");
  }
  catch(ClassNotFoundException e)
  {
    e.printStackTrace();
  }
  
  try
  {
    conn = DriverManager.getConnection("jdbc database", "user", "password");
    
    Statement stmt = conn.createStatement();
    ResultSet rset = stmt.executeQuery("QUERY");
    
    while(rset.next())
    {
      // do something
    }
  }
  catch(SQLException e)
  {
    e.printStackTrace();
  }
  finally
  {
    if(conn != null)
    {
      try
      {
        conn.close();
        conn = null;
      }
      catch(SQLException e)
      {
        e.printStackTrace();
      }
    }
  }
  
...
...
</sxh>

  * conn.setAutoCommit(true/false);
  * conn.commit();
  * conn.rollback()
  * PreparedStatement stmt = conn.prepareStatement(".... ?");
    * stmt.setString(1, "value");

  * DAO<sup>Data Access Object</sup>
  * DTO<sup>Data Transfer Object</sup>
  * JPA<sup>Java Persistence API</sup>


==== File I/O ====
  * FileReader
  * BufferedReader
  * Scanner
  * Files

  * CSV, XML, LOGGER


==== Tests ====

  * JUint
    * @Test
    * @Before
    * @After
    * @BeforeClass
    * @AfterClass
    * @Ignore
    * import static org.junit.Assert.*;
      * assertEquals()
      * fail()
      * assertThat()
      * import static org.hamcrest.CoreMatchers.*;
        * is()
  * JMockit
  * DbUnit
==== Reserved Words ====

  * data types <list-group>
  * byte
  * short
  * int
  * long
  * float
  * double
  * char
  * boolean
  * void
</list-group>

  * class & packages <list-group>
  * class
  * interface
  * enum
  * package
  * import
  * extends
  * implements
  * this
  * super
  * new
</list-group>

  * modifiers <list-group>
  * public
  * protected
  * private
  * static
  * final
  * abstract
  * native
  * volatile
  * transient
  * synchronized
  * strictfp
</list-group>

  * operations <list-group>
  * if
  * else
  * switch
  * case
  * default
  * for
  * while
  * do
  * break
  * continue
  * return
  * instanceof
  * assert
</list-group>

  * exceptions <list-group>
  * try
  * catch
  * finally
  * throw
  * throws
</list-group>

  * others <list-group>
  * const
  * goto
</list-group>

===== References =====
  * [[https://wikidocs.net/book/31|점프 투 자바]]
  * [[https://m.blog.naver.com/ehe123/221290351142|[자바 IDE] IntelliJ vs Eclipse 비교]]
  * [[https://madplay.github.io/post/difference-between-dollar-sign-and-sharp-sign-in-mybatis|MyBatis에서 샾(#{})과 달러(${})의 차이는 무엇일까?]]
  * [[https://java-design-patterns.com/principles/|Java Design Patterns]]
  * [[https://github.com/iluwatar/java-design-patterns|Design patterns implemented in Java]]
  * [[https://github.com/lesstif/TIL/blob/master/JAVA/%EC%9E%90%EB%B0%94-%EC%BD%94%EB%93%9C%EB%A5%BC-%EC%A1%B0%EC%9E%91%ED%95%98%EB%8A%94-%EB%8B%A4%EC%96%91%ED%95%9C%EB%B0%A9%EB%B2%95.md|자바-코드를-조작하는-다양한방법.md]]