Talk:Java Training Course/JT02 - Revision history

imported>Gfis at 12:03, 23 October 2017

2017-10-23T12:03:28Z

← Older revision		Revision as of 12:03, 23 October 2017
Line 29:		Line 29:
	It will output the desired text:		It will output the desired text:
	Hello, World!		Hello, World!
			===Fat Client===
			* [https://de.wikipedia.org/wiki/JavaFX#Hello_JavaFX_World.21 JavaFX] example on de.wikipedia.org

imported>Gfis: explanation of names

2017-09-24T09:42:45Z

explanation of names

← Older revision		Revision as of 09:42, 24 September 2017
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	} // main		} // main
	} // HelloWorld		} // HelloWorld
	It must be stored in a file <code>HelloWorld.java</code>, since Java source files must have the same name as the class contained in it.		That program must be stored in a file <code>HelloWorld.java</code>, since Java source files must have the same name as the class contained in it. Usually there is exactly one class in one Java source file.

	~~Upper/lowercase letters are~~ (~~very~~) ~~important in Java~~.		With abbreviated names and minimal spacing the program almost fits on a single line:
			public class HW{public static void main(String[]a){System.out.println("Hello, World!");}}

	For the separation of words in Java names, underscore characters would be possible, but they are deprecated. The CamelCase		Upper/lowercase letters are different. Their distinction is (very) important in Java.
	convention of embedded uppercase letters is used instead.
			For the separation of words in Java names, underscore <code>_</code>characters would be possible, but they are deprecated. The ''CamelCase'' convention of embedded uppercase letters is used instead in names. Names may contain:
			* letters (the first character of a name must be a letter), even Unicode (non-ASCII) letters
			* digits
			* the underscore <code>_</code>, but this is deprecated or at least unusual
			* no hyphen <code>-</code> or dot <code>.</code> (the dot is used for property and method qualifying)

			By convention, there are 3 types of names:
			* starting with lowercase: for ordinary variables, properties, methods, packages
			* starting with uppercase: for classes
			* all upperccase: for constants (static final)

	The program is compiled into a file <code>HelloWorld.class</code> by		The program is compiled into a file <code>HelloWorld.class</code> by

imported>Gfis: new

2017-09-22T18:43:30Z

new

New page

An almost minimal Java program is:
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!");
} // main
} // HelloWorld
It must be stored in a file <code>HelloWorld.java</code>, since Java source files must have the same name as the class contained in it.

Upper/lowercase letters are (very) important in Java.

For the separation of words in Java names, underscore characters would be possible, but they are deprecated. The CamelCase
convention of embedded uppercase letters is used instead.

The program is compiled into a file <code>HelloWorld.class</code> by
javac HelloWorld.java
The classfile maybe run by
java HelloWorld
It will output the desired text:
Hello, World!