java basics @ mlab, 15-19 Nov 1999, juhuu@katastro.fi




 variables? 
 

	char

		one character in a string


	boolean

		true  or  false



	integral / integer

		byte  short  int  long

		byte, from -128 to 127 
		short, from -32768 to 32767
		int, from -2147483648 to 2147483647
		long, from -9223372036854775808 to 9223372036854775807



	floating point / decimal numbers

		float  double




	most commonly used: char, boolean, int, double










 objects? 


	java is an object oriented language. the definitions
	of objects and their methods (functions) are called classes.	

	a representative of a class is called an instance.









					class2				
					    public method1
					    public method2

	class1
	    private method1
	    private method2
	    public method1
	    public method2
					class3
					    private method1
					    private method2
					    public method1
					    public method2
	





	some very useful java classes:

	( you can find information about these and others from
	jdk 1.02 API documentation )

	java.lang.Math
		
			Math class, mathematical functions

	java.lang.String
		
			String class, string manipulation functions

	java.util.Random

			Random class, random number generator

	java.util.Vector

			Vector class, array that can grow and shrink dynamically

	java.awt.Graphics

			Graphics class

	java.awt.Color

			Color class

	java.applet.Applet

			Applet class