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2006 January – April
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The Java Development Tools The Java Development Tools projectproject
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What we'll cover hereWhat we'll cover here
The JDT environment
Creating and running a program
Automating testing with JUnit
Using Ant and javadoc
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© 2006 IBM Corporation.Making the most of Making the most of
The JDT environmentThe JDT environment
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The Java Development ToolsThe Java Development Tools
A set of tools for writing, compiling, testing, and debugging Java code. Note: Compiling happens automatically whenever you save your
code. 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 perspectives for Java development are Java and Debug. There are also the Java
Browsing and Java Type Hierarchy perspectives.
We'll look at the Java perspective now; we'll cover the Eclipse Debugger later.
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The Java perspectiveThe Java perspective
Syntax-aware Java editor
Class hierarchy
Class outline
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The Java editorThe Java editor
As you'd expect from a world-class IDE, Eclipse has a color-coded Java editor.
As you type, it automatically highlights the Java syntax and indents your code.
If there are errors, they're indicated when you save the file (if not before).
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The Java editorThe Java editor
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Code assistCode assist
If you type Ctrl+Space, Eclipse shows you the relevant method signatures 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 source code.
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GlobalizationGlobalization
Eclipse has an "Externalize Strings" function that helps you manage translation or localization of your projects.
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Other great featuresOther great features
Generate getters and setters automatically
"Quick Fix" certain problems
Automatically organize import statementsAdd imports as necessary, remove unused imports, specify which
imports are used
Refactoring codeRename classes, methods, fields
Create an interface from a class
Move classes, methods, fields
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2006 January – April
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Creating and running a Creating and running a programprogram
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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; compiling and building is not a
separate step.
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Creating a Java projectCreating a Java project
Start with FileNew Project…
Choose Java Project, give it a name and click Finish.
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Creating a Java ProjectCreating a Java Project
If you click Next after you give your project a name, you'll see other options. 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 the Package Explorer, then choose NewPackage…
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Creating a Java packageCreating a Java package
Enter a name for your package.
If you break Java style rules (maybe your package begins with an uppercase letter), Eclipse reminds you.
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Creating a Java packageCreating a Java package
Your new package appears in the Package Explorer beneath your project.
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Creating a Java classCreating a Java class
To create a Java class, right-click on your new package in the Package Explorer, then choose NewClass.
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Creating a Java classCreating a Java class
Enter a name for your class.
Eclipse reminds you of style rules here as well.
You can set the details of your class, including its superclasses, visibility and interfaces.
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Creating a Java classCreating a Java class
Your new class appears in the Package Explorer beneath your package.
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 package and a new class at the same time.
Simply create a new class and enter a new package name in the wizard.
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Running your codeRunning your code
To run your code, right-click on the Java file, then choose Run AsJava Application.
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Running your codeRunning your code
Because this is a console application (it uses System.out.println), you'll see the output in the Console view. By default, System.outSystem.out is displayed in blackin black, System.errSystem.err is
displayed in redin red and System.inSystem.in shows up in greenin green.
If the Console doesn't appear, you can open it through WindowShow View…
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Re-running your codeRe-running your code
Once you've run your code, a reference to it appears in the Run menu. You can click your program's name in the Run History menu to 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 run configuration.
This lets you set command-line parameters, JVM options, etc.
Select your project in the Package Explorer, then choose RunRun…
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Scrapbook pagesScrapbook pages
You can create a scrapbook page with the Java tools. A scrapbook page lets you enter and execute lines of Java code without building a class to hold them.
The wizard to create a new scrapbook page is under New JavaJava Run/Debug.
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Scrapbook pagesScrapbook pages
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 this example, we've highlighted the entire line of code; executing it writes to the console.
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Scrapbook pagesScrapbook pages
If you choose Inspect, the scrapbook page shows you the value of whatever you've highlighted. In this example, we've only
highlighted Math.PI, not the whole line of code.
Display inserts the value of whatever you've highlighted.
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Automating testing with JUnitAutomating testing with JUnit
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Automating testing with JUnitAutomating testing with JUnit
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 test casesCreating test cases
Right-click on a Java file and choose New Other…
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Creating test casesCreating test cases
Select Java/JUnit on the left and TestCase on the right, then click Next.
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Creating test casesCreating test cases
When you create a JUnit test case, you name the test case (it's a Java class) as well as the Java class tested by the test case.
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Creating test casesCreating test cases
Eclipse gives you a list of all the public methods in your class and its superclasses. You decide which ones should be part of the JUnit test class.
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Creating test casesCreating test cases
In this example, we ask Eclipse to generate a JUnit TestCase 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 return the string "Hello, World!"
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Running test casesRunning test cases
Our test case is the Java class TestHelloWorld.
To run the class, select the test class in the Package Explorer, then choose Run AsJUnit Test.
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Running test casesRunning test cases
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 is an ordered collection of TestCases.
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Using JUnitUsing JUnit
You define more TestCases and TestSuites as your project progresses.
You run the JUnit tests to make sure any changes you've made haven't broken your code.
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Using Ant and Using Ant and javadocjavadoc
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Using AntUsing Ant
Ant (ant.apache.org) is an XML- and Java-based build tool.Designed to have the same functionality as make 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.
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Using AntUsing Ant
An Ant build file (named build.xml by default) can define a number of targets.
You can define which target gets built from the command line (or the Eclipse equivalent), or let Ant figure out which one should be created.
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Using AntUsing Ant
Once you've created your build.xml file (or whatever you choose to call it), you can right-click on it and choose Run Ant…
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Using Using javadocjavadoc
You can export your project to javadoc.
When you do this, Eclipse runs javadoc against your code and exports the generated files to the directory you choose.
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Using Using javadocjavadoc
When you generate the javadocs, you specify which packages and classes should be processed.
You can also decide which class members are processed (public, protected, private)
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Using Using javadocjavadoc
You can customize the files that are generated, such as index pages or navigation bars.
If you want, you can create links to the standard Java libraries.
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Using Using javadocjavadoc
The generated documentation is put in the docs folder of your project by default.
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SummarySummary
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SummarySummary
We've covered (although very quickly) the Java development functions in Eclipse, including:Various automatic coding features
How to create and run Java code
Automating testing with JUnit
Using ant and javadoc inside Eclipse