7 Getting Started with Developing Java Applications

From the JDeveloper IDE, use Swing and AWT components to build, deploy, and publish desktop-based GUI applications, and use Java Web Start to build Java client applications.

JDeveloper enables you to build and assemble Java applets and client applications using JavaBeans and interactive, desktop-based GUI applications using Swing and AWT components. You can also create and run Java client applications with Java Web Start within the JDeveloper IDE.

JDeveloper displays Java source files in the Java Source Editor. Use the editor to edit Java code, and use the Preferences Dialog to customize the editor .

The Java Source Editor displays Java source files, and facilitates editing of Java code. The Java Source editor is a specialized form of the generic Source Editor that JDeveloper provides for editing source code across several technologies, including XML, JSP, and HTML.

Double-clicking a node in the Applications window either opens or brings the default editor to the foreground. When a file is open in the Source Editor, its corresponding elements are displayed hierarchically in the Structure window. Double-clicking a node in the Structure window shifts the focus to the definition of that element in the Source Editor.

You can customize the behavior of the Java Source Editor by specifying preferences in the Preferences Dialog.

Use Java Code Insight to filter irrelevant information, to speed up coding, to complete code using completion insight, to select instance and static members using member insight, and to edit parameters using parameter insight. Use Preferences from Tools to edit Code Insight settings, or to view or change accelerators.

With Java Code Insight, you can filter out unnecessary information such as top-level packages, imported classes, default Object methods, deprecated items, and emphasize more key detail such as local variables, locally declared members, overloaded methods.

You can use Code Insight to speed up the process of writing code. Code Insight has two varieties: completion insight and parameter insight. You can enable or disable each independently and set the delay in seconds for each to appear when the cursor is paused at an appropriate insertion point.

To invoke completion after typing the period separator or, in the default keymap, press Ctrl+Space. To invoke parameter insight, pause after typing an opening (the left) parenthesis or, in the default keymap, press Ctrl+Shift+Space. To exit either type of insight at any time, press Esc. Note that if you change your keymap ping, these keyboard accelerators may change. You can click QuickDoc, located at the bottom right of the completion insight list, to display the Javadoc for the currently selected element

After a method has been completed by completion insight, the source editor automatically fills in the parameters based on the method code.

You can tab between these parameters, and edit them manually or using parameter insight. The source editor will automatically add an import if it can find only one exact match for an unresolved reference to a class. You can set preferences for this feature in the Preferences Dialog.

You can also use and configure member insight, the Java-specific implementation of Code Insight's completion insight, and you can choose to display deprecated members or not in Code Insight's parameter insight window.

Member insight provides you with a list of which instance and static members (fields, methods, inner classes) are accessible from a given statement context. For example, it tells you which methods you can call from any given method.

To change Code Insight settings or to view or change accelerators, from the main menu choose Tools > Preferences to open the Preferences dialog and then navigate to the appropriate page.

Press Shift and point the mouse pointer at a variable or method to see its definition.

You can hold down the Shift key and then hover over a variable or method to show its definition in a ghost window. This feature makes it convenient to quickly view code without moving cursor focus from your current code.

Figure 7-1 Code Peek

Description of "Figure 7-1 Code Peek"

Scroll vertically to see a window alongside the scroll bar that displays the methods that are in view and the name of the method that will next appear in view.

An InfoTip, with details of the item in focus, pops up when the mouse pointer is positioned over an item.

An InfoTip is a pop-up window that reveals additional detail about an item in the application, for example, text in the Java Source Code editor and the overview gutter. You display the InfoTip by pointing or hovering over the item with your mouse cursor. It remains visible until you move the mouse away or click elsewhere in the UI.

Figure 7-2 InfoTips

Description of "Figure 7-2 InfoTips"

Use the Incremental Find Forward or the Incremental Find Backward options in Search to search for an item forward or backwards.

Shortcut keys or accelerators are a keyboard alternative to mouse device operations and navigation. Use Preferences in Tools to go to the Shortcut Keys page to view or change existing accelerators, and to the Code Editor from the Category list to view or change accelerators for an editor.

Use Bookmark to see all the bookmarks in the Bookmarks window. The window also shows the line number and the name of the bookmarked method.

Browse imported classes and interfaces, member fields and methods, and local variables using Go to Declaration that takes you to the identifier source in an open Java file. JDeveloper reverse-engineers the class file for a source that is unavailable.

import javax.swing.JButton
...
JButton b1 = new JButton();
...
b1.SetText: ('OK');

In application development, use Code templates to insert pre-written code that adapts to surrounding code. Use Preferences in Tools to create and edit a code template, and view the complete list of code templates in the Code Editor Help.

Use Preferences in Tools to customize the behavior of the Java Source Editor, and to define the settings for the general source editing environment. Use the procedure to set the options for Code Insight as it applies to Java.

1. From the main menu, choose Tools > Preferences.
2. In the Preferences dialog, expand the Code Editor node.

   A list of selectable options displays, for example, Bookmarks and Code Templates.

3. Click an option and choose options that appear on the new page that displays.
4. Click OK when you are finished.

The Java Source Editor displays Java source files and the tools to create and edit Java code. The table lists the Toolbar options that JDeveloper provides.

In the Java source editor, click Quick Outline Toolbar to see the Quick Outline window. The window provides a structural view of the available methods and fields of a class and its super classes.

Clicking the Quick Outline Toolbar icon to the right of the Find field in the Java source editor displays the Quick Outline window shown in Figure 7-4.

Figure 7-3 Quick Outline Icon

This window floats just above the code and contains a tree of the available methods and fields of the current class and its super classes. You can instantly start typing in a filter field to reduce the visible items, allowing quick and easy selection for navigation to the place.

Figure 7-4 Quick Outline Window

Description of "Figure 7-4 Quick Outline Window"

Table 7-2 lists the available icons and options.

For Swing or Abstract Window Toolkit applications, use the Java UI Visual Editor to view and edit the visual components of the user interface.

The Java UI Visual Editor displays the visual components of a user interface in editing mode. See Editing with the Java Visual Editor .