03-Java Development Tools

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Presented by IBM developerWorks

ibm.com/developerworks/April June 2006

2006 IBM Corporation.

Making the most ofMaking the most of

The Java Development Tools projectThe Java Development Tools project

3-2 Making the most of 2006 IBM Corporation.


What we'll cover hereWhat we'll cover here

The JDT environment

Creating and running a program

Scrapbook pages

Automating testing with JUnit

Using Ant and javadoc


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The JDT environmentThe JDT environment



The Java Development ToolsThe Java Development Tools

A set of tools for writing, compiling, testing, and debugging Javacode.

Note: Compiling happens automatically whenever you save yourcode. It's not a separate step.

The Eclipse SDK includes the Java tools. See eclipse.org/jdt if

you want to learn more about the project.


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JDT perspectivesJDT perspectives

The most useful perspectivesfor Java development are Javaand Debug.

There are also the JavaBrowsing and Java TypeHierarchy perspectives.

We'll look at the Javaperspective now; we'll cover theEclipse Debugger later.



The Java perspectiveThe Java perspective

Syntax-awareJava editor

Class hierarchy

Class outline


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Code generationCode generation



Code assistCode assist

If you type Ctrl+Space, Eclipse shows you the relevant methodsignatures and the javadoc for each.

This works for code you write as well as the standard Java libraries.

You don't have to run javadoc against your code for this to work.

The documentation above comes from the comment in the sourcecode.


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Quick fixQuick fix

For many common problems,Eclipse can offer fixes for you.

If apackage statement doesn'tmatch a .java file's location,

Eclipse will move the file orupdate thepackage

statement.

If you're missing an import

statement, Eclipse canautomatically add it.

If a Quick Fix is available, thered X will have a light bulb iconbehind it.



Organize importsOrganize imports

If you use a Java class withouta corresponding importstatement, Eclipse will addthem for you automatically.

By default Eclipse importsjava.io.OutputStream, not

java.io.*.

If you remove all instances of aclass and invoke OrganizeImports again, Eclipse removesthe import statements you

don't need.


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CodeCode refactoringrefactoring

Eclipse can refactor your code in several useful ways:

Rename classes, methods, fields

Create an interface from a class

Move classes, methods, fields



GlobalizationGlobalization

Eclipse has an "ExternalizeStrings" function that helps youmanage translation orlocalization of your projects.


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Creating and running a programCreating and running a program



Creating and running codeCreating and running code

It's a short process:

1. Create a Java project

2. Create a Java package

3. Create a Java class in that package

4. Set up a run configuration

5. Run your code

This can be confusing to

newcomers; compilingand building is not a

separate step.


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Creating a Java projectCreating a Java project

Start with FileNewProject

Choose Java Project, give it aname and click Finish.



Creating a Java ProjectCreating a Java Project

If you click Next after you give your project a name, you'll see otheroptions. You can use these to set the classpath of your project,among other things.


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Creating a Java packageCreating a Java package

To create a Java package, right-click on your new project in thePackage Explorer, then choose NewPackage




Enter a name for your package.

If you break Java style rules(maybe your package beginswith an uppercase letter),Eclipse reminds you.


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Your new package appears in the Package Explorer beneath yourproject.



Creating a Java classCreating a Java class

To create a Java class, right-click on your new package in thePackage Explorer, then choose NewClass.


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Enter a name for your class.

Eclipse reminds you of stylerules here as well.

You can set the details of yourclass, including itssuperclasses, visibility andinterfaces.




Your new class appears in the Package Explorer beneath yourpackage.

Eclipse also opens the source file for your class in the Java editor.


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A shortcutA shortcut

You can create a new packageand a new class at the sametime.

Simply create a new class andenter a new package name inthe wizard.



Running your codeRunning your code

To run your code, right-click onthe Java file, then choose RunAsJava Application.


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Running your codeRunning your code

Because this is a console application (it usesSystem.out.println ), you'll see the output in the Console view.

By default, System.outSystem.out is displayed in blackin black, System.errSystem.err isdisplayed in redin red and System.inSystem.in shows up in greenin green.

If the Console doesn't appear, you can open it throughWindowShow View



ReRe--running your coderunning your code

Once you've run your code, a reference to it appears in the Runmenu. You can click your program's name in the Run History menuto run it again.

Run Last Launched (Ctrl+F11) does the same thing.


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Creating a run configurationCreating a run configuration

In some cases you need a runconfiguration.

This lets you set command-lineparameters, JVM options, etc.

Select your project in thePackage Explorer, then chooseRunRun



Creating a run configurationCreating a run configuration

Click Java Application, then New. You'll see a dialog that lets youset all the details of your application:

The Arguments tab defines command-line arguments, The Classpathtab lets you add JAR files to your classpath, and so on.

The run configuration must point to a Java class with amain()

method. If it doesn't, Eclipse can search your project for a class thatdoes.


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Scrapbook pagesScrapbook pages




You can create a scrapbookpage with the Java tools. Ascrapbook page lets you enterand execute lines of Java codewithout building a class to holdthem.

The wizard to create a newscrapbook page is under NewJavaJava Run/Debug.


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You can highlight some code, right-click on it, then choose Inspect,Display or Execute.

Our sample code here is System.out.println("Here's the value of PI: " + Math.PI);

If you choose Execute, the selected code is executed. In thisexample, we've highlighted the entire line of code; executing it writesto the console.




If you choose Inspect, thescrapbook page shows you thevalue of whatever you'vehighlighted.

In this example, we've onlyhighlightedMath.PI, not the

whole line of code.

Display inserts the value ofwhatever you've highlighted.


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Automating testing withAutomating testing with JUnitJUnit



Automating testing withAutomating testing with JUnitJUnit

JUnit was created by programming legends Kent Beck

and Erich Gamma.

It makes it easy to implement Test-Driven Development

(TDD), (sometimes called Test First Development).

Eclipse has JUnit support built in.


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Creating a test caseCreating a test case

Right-click on a Java file andchoose New Other




Select Java/JUnit on the left and TestCase on the right, then clickNext.


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When you create a JUnit test case, you name the test case (it's aJava class) as well as the Java class tested by the test case.




Eclipse gives you a list of all the public methods in your class and itssuperclasses. You decide which ones should be part of the JUnit testclass.


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In this example, we ask Eclipse to generate a JUnitTestCase for the getGreeting() method.

The complete testGetGreeting() method is:

public void testGetGreeting() {

HelloWorld hw = new HelloWorld();

assertEquals("Hello, World!",

hw.getGreeting());

}

We're saying that getGreeting() should always returnthe string "Hello, World!"



Running a test caseRunning a test case

Our test case is the Java class TestHelloWorld.

To run the class, select the test class in the Package Explorer, thenchoose Run AsJUnit Test.


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Running a test caseRunning a test case

The results of running your test case appear in the JUnit view.

Green is good

You can also create and run JUnit TestSuites. A TestSuite isan ordered collection of TestCases.



UsingUsing JUnitJUnit

You define more TestCases and TestSuites as your

project progresses.

You run the JUnit tests to make sure any changes you'vemade haven't broken your code.


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Using Ant andUsing Ant and javadocjavadoc



Using AntUsing Ant

Ant (ant.apache.org) is an XML- and Java-based

build tool.

Designed to have the same functionality asmake without its quirks

You don't need a tab character at the start of each line, for example.

You can extend Ant to do other tasks if you want.

An Ant build file (namedbuild.xml by default) can

define a number of targets.

You can define which target gets built from the commandline (or the Eclipse equivalent), or let Ant figure out whichone should be created.


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Using AntUsing Ant

Once you've created yourbuild.xml file (or whatever

you choose to call it), you canright-click on it and choose RunAnt



UsingUsing javadocjavadoc

You can export your project tojavadoc.

When you do this, Eclipse runsjavadoc against your code

and exports the generated filesto the directory you choose.


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When you generate thejavadocs, you specify which

packages and classes shouldbe processed.

You can also decide whichclass members are processed(public, protected, private)




You can customize the files thatare generated, such as indexpages or navigation bars.

If you want, you can create linksto the standard Java libraries.


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The generated documentation is put in the docs folder of your project

by default.


ibm.com/developerworks/

April June 2006



SummarySummary


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SummarySummary

We've covered (although veryquickly) the Javadevelopment functions in Eclipse, including:

Various automatic coding features

How to create and run Java code

Using scrapbook pages

Automating testing with JUnit

Using ant and javadoc inside Eclipse

Documents

03-Java Development Tools