Introduction to the JDeveloper IDE

Purpose

This tutorial provides a tour of the major components in the Oracle JDeveloper 11g IDE, and shows you how they can be used to build a basic application.

Time to Complete

Approximately 45 minutes.

Topics

This tutorial covers the following topics:

	Overview
	Prerequisites
	Launching JDeveloper 11g
	Creating Your First Application
	Creating Your First Java Class
	Using the Source Editor with Your Java Class
	Debugging Java Programs
	Managing Files
	Summary

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Overview

In the tutorial, you learn how to create a simple Java class. Using your new class, you then explore some of the features of the JDeveloper IDE, including Code Assist and the Debugger.

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Prerequisites

Before you begin this tutorial, you should:

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Launching JDeveloper 11g

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Creating Your First Application

The application is the highest level in the control structure. It is a view of all the objects you need while you are working. An application keeps track of all your projects while you are developing your Java programs.

Applications are stored in files with the extension .jws. When you open JDeveloper, the last application used is opened by default, so that you can resume where you left off.

When creating a new application you have the option to base it on a template. The application template you select determines the initial project structure, that is, the named project folders within the application.

In JDeveloper you always work with projects contained within an application. A JDeveloper project is a logical grouping of related files. You can add multiple projects to an application to easily access, modify and reuse your source code.

The Application Navigator is the main JDeveloper window from which you access the components of your application. The structure of the Application Navigator is hierarchical and supports, for a given application, projects, images, .html files, and many more. By default the Application Navigator displays on the left side of the IDE.

To create an application, perform the following steps:

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Creating Your First Java Class

To create a new Java class, perform the following steps:

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Using the Source Editor with Your Java Class

Editors are where most of the application development work takes place; this is where you write code and design user interfaces. In this topic you explore some of the features of the Java Source Editor.

	Using code templates
	Compiling and running your Java class
	Working with Code Assist
	Searching and Highlighting Code
	Refactoring code
	Viewing code modification history
	Navigating through code

Using code templates

Code templates assist you in writing code more quickly and efficiently while you are in the source editor. You can edit existing templates or create your own. This topic shows you how to use some of the existing code templates in the Dog class.

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Compiling and running your Java class

When you successfully compile a .java file, you create a .class file in the \src directory of the project. Compiling a class in JDeveloper automatically saves the .java file as well. When you run a class, it is automatically compiled and saved.

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Working with Code Assist

Code Assist examines your code in the editor and provides assistance to fix common problems. Here you use the Dog class to explore some examples of the suggestions that are offered.

1.	Create a Cat object. At the start of the main method, just after the first curly brace, press [Enter] to create a new line. In the new line, enter the following code: Cat myCat = new Cat();
2.	Notice that the red wavy lines and margin indicators have again appeared. Place the mouse over a margin indicator to see what the problem is from the code popup window. Notice that the popup box displays the problematic lines as well as telling you what the problem is.
3.	Hover your mouse over the light bulb icon in the left hand margin of the 'cat' line. A message tells you that 'quick fixes and code assists' are available for this line.
4.	Click the icon to see what they are. You need a Cat class to instantiate a Cat object. If you click on the first suggestion in the list offered, JDeveloper creates a class called Cat. On this occasion you don't want to create the Cat class immediately, so you remind yourself to do it later by setting yourself a task: press [Enter] after new Cat(); to open a new line and in the new line enter the following code: //TODO create a Cat class
5.	Select View | Tasks to see a list of tasks that you have created.
6.	The Tasks window displays a list of the tasks you have created (in this case, it is your only task).
7.	If you double-click a task in the list, JDeveloper takes you to the relevant task, inserting the cursor at the start of the line.
8.	Notice the pink marker at the top right margin of the editor. It indicates where you have created a task. Hover over the marker with the mouse to see what the task is.
9.	Comment out the line that creates the Cat object. Notice that the red markers have now disappeared, to be replaced by a green marker indicating that there are no errors in your code.
10.	Check out the new toolbar in the code editor. Add two variables to the class. Hit [Enter] to create a new line after the class declaration. Declare two variables as follows: String name; int age;
11.	In the code editor, right click and select the Generate Accessors option from context. The generate accessor option is also available from the code editor toolbar using the Generate Accessors icon.
12.	In the Generate Accessors dialog, check the Dog box to generate Getter and Setter methods for both variables. Notice that you can define the scope for the methods, and define other properties to be implemented in the setter methods such as involving listeners and verifying the new value. Click OK. Getter and Setter methods are generated into the Dog class.
13.	Right click within the code editor and from context select Source --> Generate Constructor from fields.
14.	In the Generate Constructor from Fields dialog, select both fields and click OK.
15.	The new constructor method is added to your code.
16.	Click the Undo button since we don't need this constructor method.

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Searching and Highlighting code

Using the code editor, you can search for text and display all occurrences of the search criteria. You can also use a highlighting facility that retrieves all occurrences of an object.

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Refactoring code

Refactoring is an editing technique that modifies code structure without altering program behavior. A refactoring operation
is a sequence of simple edits that transforms a program's code but keeps it in a state where it compiles and runs correctly.
JDeveloper provides a collection of refactoring operations.

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Viewing code modification history

JDeveloper has a built-in history feature. This local history does not require a version control system to provide a recent change record and visual "diff" between versions. Versions are automatically created based on user interactions such as Save, Compile, Rename, and so on.

1.	Notice the three tabs at the foot of the editor window. Click the History tab.
2.	The History window displays. The top part of the window contains a list of revisions and dates, while a list of changes to the code displays in the bottom part of the window. The two windows are synchronized, so that the detail in the bottom part of the window matches the selection in the top part. The revisions for the selected date and time are summarized in the status line at the bottom of the IDE, in this case 6 differences: 3 added, 0 removed, 3 changed.
3.	The lilac-colored boxes indicate changes to the code. In the top portion of the window, select Introduce Parameter near the top of the list. In the bottom left portion of the editor, position your mouse over the green right-pointing arrow in the lilac box that contains the sayHi() method declaration. Notice that a message displays, indicating that clicking the green arrow enables you to replace the adjacent difference. In this case, clicking the green arrow would revert the sayHowDoYouDo() method to sayHi(). Don't revert now.
4.	The green boxes indicate additions to the code. In the top portion of the window, select Load External State near the bottom of the list. In the bottom of the window, select the //Cat myCat = new Cat(); line in the green box in the right hand window. Hover over the red X with your mouse. Notice the message indicating that to delete the addition(s), you click the X.

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Navigating through code

JDeveloper provides easy ways to navigate to related code and to Javadoc, and the ability to expand or contract sections of code, improving navigability in large programs. To explore these features, perform the following steps:

1.	Click the Source tab for the Dog.java file in the editor. You can navigate from one part of the code to another related part. One example of this is navigating from a method to its declaration in an interface. A method that implements a declaration from an interface displays a callout icon in the left-hand margin. Clicking this icon takes you to where the method is declared. Click the arrow icon next to the sayHowDoYouDo() method in the Dog.java file.
2.	JDeveloper takes you to the IntAnimal interface where the method is declared and highlights the appropriate line for you.
3.	To return to where you were in the Dog class, click the green Back button in the toolbar. You can also Navigate backward or forward using the [Alt] + [left] or [right] arrow key.
4.	You can also navigate to the Javadoc for a given element. In the Dog.java file in the editor, right-click within the sayHowDoYouDo() method. From the context menu, choose Quick Javadoc.
5.	The Javadoc popup window displays additional information about the selected method.
6.	Click the String link to get more info about the String class. Click within the code editor window to remove the doc 'ghost' window.
7.	Click [Ctrl]+[-] (minus) key to popup the Go to Java Class dialog. It allows you to display Source or Javadoc information of the selected class. In the Name field type String then Enter on the java.lang.String highlighted suggestion.
8.	The source code for the String class opens in the editor. Close the String.java tab.
9.	Code folding enables you to expand and contract sections of code, making large programs more manageable. Place your mouse in the space between the dotted and solid lines to the left of the Cat line. Notice that a blue vertical line displays beside the main method body.
10.	Click the minus (-) sign at the top of the vertical blue line to contract this section of code.
11.	Hover over the plus (+) sign next to the contracted section of code. The contracted lines of code display in a blue shaded box.
12.	The new Quick Outline Navigator enables you to quickly navigate to methods and fields of a class and its super classes. In the code editor toolbar click the Quick Outline icon. The Quick Outline 'ghost' window displays.
13.	Click the Show Methods icon (first icon from the left) to see all the methods in the Dog class.
14.	Filter by typing ge in the field.
15.	Use the down arrow key to select the getName() method, then Enter. That's a new feature that provides built-in navigation in the class you are looking at.
16.	Back in the code editor, double-click within the ellipses of the main() {...} method. JDeveloper expands the collapsed code.

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Debugging Java Programs

1.	Set a breakpoint in the Dog.java file. To do this, click in the margin to the left of the line: System.out.println(count + myDog.sayHowDoYouDo("Kate")); The breakpoint icon, which looks like a red ball, is displayed in the margin.
2.	Right-click in the source editor and select Debug from the context menu.
3.	Program execution proceeds up to the breakpoint. The red arrow in the left margin of the source editor indicates where the break is occurring. The debugger window opens and displays the debugging trace.
4.	Click the Step Over icon in the toolbar to execute the first iteration of the myDog.sayHowDoYouDo() method.
5.	Click the Debugging: MyProject.jpr tab at the bottom of the log window and then click the Log tab in the debugger window. Note that the log window displays the first woof Kate message.
6	Notice the Smart Data window to the right of the Debugging Log tab. Select the count variable, and double-click in the Value column to display the Modify Value dialog.
7.	Type 2 as the new value. Click OK.
8.	In the toolbar, click Resume to continue program execution.
9.	The count variable is incremented and exceeds its limit, so the program terminates, and the debugger disconnects.

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Managing Files

1.	From the menu, select Search | Find Application Files.
2.	In the File List tab, use the Look in field to select the scope of your search. Keep the All Projects choice.
3.	Select File Extension and type .java to retrieve all files of this type, then click Search.
4.	The Results window returns the file names corresponding to your criteria. Note that clicking on one of the file name from the list opens the file in the editor.
5.	You can indicate complex search criteria using the sign combined with the logical Match operators.
6.	You can also retrieve files recently used from the Application Navigator, click the Recently Opened Files to deploy the accordion.
7.	To retrieve a Java class, click [Ctrl] + [-] key to open a dialog.
8.	In the Name field, type Int, then select the IntAnimal.java from the list, then Enter.
9.	To retrieve a file, click [Ctrl] + [Alt] + [-] key stroke to open a dialog. In the File Name field, type D, then select the Dog.java from the list, then Enter.

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Summary

This tutorial gave you a basic programming tour of the JDeveloper IDE. You created an application, a project, and a Java class. You then used the class to explore a number of features of the Java IDE, including incorporating code templates, using Code Assist, refactoring,and reviewing your code modification history. Finally, you saw how to debug your program by using the integrated debugger.

You've learned how to:

	Create a new application and project in JDeveloper
	Create a new Java class
	Exploit some of the productivity and code assistance features of the Java IDE
	Use the Java code debugger
	Retrieve files

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