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CS7 Recitation. Cem Akkaya. Outline. Homework-0 in detail Useful links and tools Setting up your java environment. HelloWorld. //HelloWorld program public class Hello { public static void main(String[] args) { System.out.println(“Hello World") ; } }.
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CS7 Recitation Cem Akkaya
Outline • Homework-0 in detail • Useful links and tools • Setting up your java environment
HelloWorld //HelloWorld program public class Hello { public static void main(String[] args) { System.out.println(“Hello World") ; } } • java is case sensitive • Key words are reserved • main method is the starting point of each application • each statement ends with a semicolon • when you open a brace, you have to close it • the name of the java file has to be exactly the same as the class name (e.g. Hello.java)
HelloWorld • A program consists of binary instructions, which are executed by CPU • Two steps to transform our source code in machine instructions (machine language) Figure from Java Tutorial @ http://java.sun.com
HelloWorld • Java VM allows the same application (.class files) to run on multiple platforms- platform indepence Figure from Java Tutorial @ http://java.sun.com
Useful Links & Tools • Sun Developer Network (http://java.sun.com) • API Documentation (http://java.sun.com/javase/6/docs/api/) • Tutorial (http://java.sun.com/docs/books/tutorial/) • Google • Integrated Development Environments (IDEs) • Eclipse (http://www.eclipse.org/) • NetBeans (http://java.sun.com) • jGrasp (http://www.jgrasp.org/) • Notepad++ (http://notepad-plus.sourceforge.net/) - not a IDE
Setting up java environment • Download and install Java SDK from http://java.sun.com/ • Update the path environment variable • Windows Command Prompt (changes effective for session) • “set path=JAVA_DIR\bin” • “set path= %path%;JAVA_DIR\bin” • Windows Control Panel (changes are permanent) • Over Control Panel-Performance and Maintenance-System-Advanced-Environment Variables • In Unix systems setting environment variables is shell specific.