C++ Code –> Executable –> OS –> CPU

Java code –> Class –> { “JVM win”, “JVM linux”, CPU that supports JAVA} –> OS –> CPU

Java is like a application (Your Java app) running in another application (JavaVM).
so you need cmd java to run your app (.class)

javac yourJavaApp.java
java youJavaApp

• Java IDE list:
  • Eclipse (green): http://www.eclipse.org/downloads/packages/eclipse-ide-java-developers/indigosr1

• J2EE - for Enterprise system and application
• J2SE - for desktop application
  • mostly used: http://www.oracle.com/technetwork/java/javase/downloads/index.html
  • then click download Java JDK,
    • for windows x86 direct link: http://download.oracle.com/otn-pub/java/jdk/7/jdk-7-windows-i586.exe
    • idiot spoon feeding video guide if you're too lazy to google or youtube: http://www.youtube.com/watch?v=Hl-zzrqQoSE
• J2ME - for micro and mobile application

add java bin directory path to system environment or user profile environment variable:

• for win dos

   set path=c:\java\bin\location;%PATH%

  • or go system property > environment variable > user variable : path; and add java location at end
• for mac,linux

   export path=/java/bin/location:$PATH

  • or edit ~/.bash_profile, add this cmd line in it.

1. copy existing JRE to portable device
2. when use, in mac or linux terminal,

   export JAVA_HOME=/jre_dir/bin/java
   export PATH=/jre_dir/bin:$PATH 

   and in dos

   set path = %PATH%;d:\jre_dir\bin
   set JAVA_HOME=d:\jre_dir\bin\java

3. force java use local JRE instead of asking system for it

   java -verbose -jar MyApp.jar

• Data type and access
  • String

    // compare string
    new String("test").equals("test") //==> true 
    //ref: http://stackoverflow.com/questions/513832/how-do-i-compare-strings-in-java

  • Array (static type)

    int num[] = {1, 2, 3, 4, 5, 6, 7, 8, 9};
    System.out.println("size of num[]: " + num.length);

  • Dynamic array

    import java.util.ArrayList; 
    private ArrayList<Item> items = new ArrayList<Item>();
    System.out.println(items.size());

• GUI
  • Layout

    FlowLayout() //FlowLayout.LEFT, FlowLayout.CENTER, FlowLayout.RIGHT, FlowLayout.LEADING, FlowLayout.TRAILING
    GridLayout(int rows, int columns) 
    BorderLayout()
    BoxLayout()
    GroupLayout()
    SpringLayout()
    //ref: http://docs.oracle.com/javase/tutorial/uiswing/layout/visual.html

  • JTable operation:
    • method list: http://docs.oracle.com/javase/7/docs/api/javax/swing/JTable.html
    • header update ref: http://www.roseindia.net/java/example/java/swing/ChangeColumnName.shtml
      • refresh header display after update

        listTable.getTableHeader().getColumnModel().getColumn(0).setHeaderValue("IC No");
        listTable.getTableHeader().repaint();
        //ref: http://www.java.net/node/692818

    • update date ref: http://stackoverflow.com/questions/5918727/updating-data-in-a-jtable
    • fill data

      for(int i=0;i<list.length;i++){
          listTable.getModel().setValueAt(list[i].getICNO(), i, 0);
          listTable.getModel().setValueAt(list[i].getFirstName(), i, 1);
          listTable.getModel().setValueAt(list[i].getLastName(), i, 2);
          listTable.getModel().setValueAt(list[i].getTitle(), i, 3);
          listTable.getModel().setValueAt(list[i].getOrg(), i, 4);
      }

    • clear data

      for (int i = 0; i < table.getRowCount(); i++)
        for(int j = 0; j < table.getColumnCount(); j++) {
          table.setValueAt("", i, j);
        }
      }

  • user input
    • custom form dialog

      String[] n_arr=new String[3];
      JTextField icno = new JTextField();
      JTextField firstName = new JTextField();
      JTextField lastName = new JTextField();
      final JComponent[] inputs = new JComponent[] {
      new JLabel("IC NO"),
      icno,
      new JLabel("First Name"),
      firstName,
      new JLabel("Last Name"),
      lastName
      };
      JOptionPane.showMessageDialog(null, inputs, "Member Creation", JOptionPane.PLAIN_MESSAGE);
       
      n_arr[0]=icno.getText();
      n_arr[1]=firstName.getText();
      n_arr[2]=lastName.getText();

• Data validation for form guis
  • ref: http://www.codeproject.com/Articles/401805/A-framework-for-comprehensive-validation-of-user-i

• Quick GUI design guide from JFrame in NetBean (25 min)
  • http://netbeans.org/kb/docs/java/quickstart-gui.html
• Quick App Build guide with user interaction (15 min)
  • http://netbeans.org/kb/docs/java/gui-functionality.html

Some UI design Tips:

• hide and show part of UI

  panelA.setVisible(false);
  //ref: http://www.codecommit.com/blog/java/techniques-of-java-ui-development

• MVC tips:
  • Calc example: http://leepoint.net/notes-java/GUI/structure/40mvc.html

• video: http://www.youtube.com/user/VoidRealms/playlists