Eclipse Basic Help

To add a package to the project in eclipse

Create a new Java project

• File>New>Java Project

After the Java project is created

• Right click on the new created folder by the Java
• New>Package
• Now add the new Java Package name.
• You can use dots (.) to specify multiple folders.
• After the package is added you will see a Tree Hierarchy of the folders which you can see when you go to the folder or when you add the class file inside it.

To add the class file

• Right click on the last folder and click NEW> Class
• This will create the new class for the project.

Running you Java program outside Eclipse(create a jar File)

• To run your Java program outside of Eclipse you need to export it as a jar file. Select your project, right click on it and select "Export".
• Select JAR file, select next. Select your project and maintain the export destination and a name for the jar file. I named it "myprogram.jar".

Adding external library (.jar) to the java classpath

• From the menu select File > Import > File system. Select your jar and select the folder lib as target.
• Select your project, right mouse click and select properties. Under libraries select "Add JARs".
• If you find some errors in the import then find the jar in eclipse/plugin folder for the missing jar files.

To change the JRE you are currently working on

• Window > Preferences > Java >Installed JREs
• Add the new installed JRE. Check the one you want to use.
• Now go to
• Window > Preferences > Java > Compiler
• change the "Compiler compliance level" to the one you are using

To fix the JRE not compatible with workspace .class file compatibility: 1.6 error

• Window > Preferences > Java > Compiler and change the "Compiler compliance level" to 5.0

REFERENCE:

1. http://www.vogella.de/articles/Eclipse/article.html