eclipse Tips

1. eclipse Tips

2. What is eclipse? • Eclipse is a popular IDE (Integrated Development Environment) that we will use to create, compile, execute, and test our Java code. • It has many advanced features that make it an ideal tool not only for the academic setting but also for the corporate world. • We will be using only a small subset of its capabilities. To learn more about eclipse, visit their website at www.eclipse.org, or take advantage of its extensive help features.

3. Installing eclipse • Note: You can skip this step on the school computer, since Java and eclipse are already installed on it • Prerequisite for eclipse: Download the Java Development Kit (JDK) if you don’t already have it • http://java.sun.com/javase/downloads/index.jsp • Select JDK 6 Update 21 (listed under Java Platform, Standard Edition). Click on “Download JDK” button.

4. Installing eclipse(continued) • Download eclipse (or copy it from the school’s S: drive). Pick one of the 2 options below: • To download: • http://www.eclipse.org/downloads/ • Select Eclipse Classic 3.6.0 (there is an option for “Windows” to the right of this option – select it if you have Windows) • Or you can copy eclipse from the school’s shared drive: • Copy folder S:\StudentShare\AP Computer Science\Eclipse to your flash drive • Copy the entire folder to your home PC

5. Jar files • Jar files are libraries that store compiled code that you can use in your own programs. • At school, copy the jar files to your H: drive. One recommendation is to create a folder named H:\JarFiles and copy any needed jar files to this folder. • Note: The KarelJRobot.jar file is located on my website. You can download it from my Daily Lesson Plan page. You can copy this file to H:\JarFiles for later use in programs.

6. workspace • Projects • Packages • Classes workspace • A workspace is used to store all of your Java classes. • At school, create a workspace on your H: drive. Do this by creating a new folder named H:\workspace . • To begin with, there should be no files in this folder

7. Launching eclipse • To launch eclipse, select Start > Programs > Student Applications > eclipse • When you first open eclipse, it may ask you to select the workspace. While at school, select H:\workspace. • If a Welcome screen appears, you can either browse through some of the topics or close it to get to the main eclipse windows.

8. Projects • workspace • Projects • Packages • Classes • A Java project contains source code and related files for building a Java program. The Java project is a folder underneath the workspace folder. • To create a new Java Project: • Select File > New > Java Project • Enter the name of the project • All radio buttons should be on their top option • Remember to include the External jar file (listed under the Libraries tab > Add External JARs). Note: While at school, the jar file should be located on your H: drive • Press “Finish”.

9. Packages • workspace • Projects • Packages • Classes • A Java package is used to organize related Java classes. It is a folder underneath the Java project folder. • To create a new Java Package: • Single click on the project • Select File > New > Package • Enter the package name. • Press “Finish”.

10. Classes • workspace • Projects • Packages • Classes • A Java class is the programming code. The source code has an extension of .java and is located in the package folder. It is a text file and can be edited with any text editor. • To create a new Java class: • Single click on the package • Select File > New > Class • Enter the class name. • Press “Finish”.

11. Saving/Compiling/Running a class • workspace • Projects • Packages • Classes • A class can always be saved, even if there are errors. To do this, press the Save button. • Saving the class will automatically try to compile it. If it is free from errors, it will be compiled successfully and a file with the extension .class will be created in thhe package folder. • To run a new Java class: • Note: The class must have a main method to be run. • Make the class the active class: Double click on it in the Package explorer to make it active in the window. • Select Run > Run as > Java application

12. Proper Indentation • workspace • Projects • Packages • Classes • It is good practice to indent code so that a human can more easily read it. The methods within a class should be indented as well as the statements within a method. • Eclipse can help you with indentation: • Show your class in the active window. • Optionally, select the lines of code to be indented. Otherwise, the entire class will be corrected. • Select Source > Correct Indentation • The end result is that your code should be indented properly.

13. Copying Classes between School and Home • Since there are times when you will want to continue your work at home, you will need to be able to transfer your code back and forth. This is where your flash drive becomes handy. • To reduce confusion, keep the folder structure on your flash drive the same as the folder structure on H:\workspace. • Use file manager to locate the Java source file (that has extension .java) within the package folder. • Copy only the .java files (not the .class files) to your flash drive folder. • You can then copy these files to your package folder on your destination computer. • Note: After you launch eclipse, it is important to refresh the project and package. Otherwise, the new code may not be seen within eclipse: • Single click on the project and select File > Refresh (or press F5). • Single click on the package and select File > Refresh (or press F5).