.Open The Predefined Classes in Java
Much of the usefulness of Java comes from the packages of
useful classes. objects, and functions that already exist.

The class library is still evolving
- see
.See http://java.sun.com/j2se/1.4.2/docs/api/index.html
for the current library.

A complete new language and $API is expected in the summer of
2004:
.See http://java.sun.com/j2se/1.5.0/docs/api/index.html
and I have connected links on this page to both versions.

The class library describes an $API.
API::=Application Programmers Interface.
In otherwords it is intended that a programmer should use these
classes to do most of the work - GUI interfaces, networking, 
audio, and so on.  More interesting is that the same code
will automatically assume the look-and-feel of the client machine.
If someone is using Windows 95 then they will see the usual
file open dialogue.  On UNIX it will look like a UNIX dialogue,
and on a Mac like a Mac Dialogue.  Even the form of buttons
will be adjusted to what the client expects rather than
what the programmer thinks is right.

The following pointers are to descriptions of the
current release of the Java classes.

. Language Foundation Classes
Package java.lang contains essential Java classes, including numerics, 
strings, objects, compiler, runtime, security and threads.  Unlike other 
packages, java.lang is automatically imported into every Java program.
. Input/Output package java.io
Package java.io provides a set of input and output streams to read and 
write data to files, strings, and other sources.
. Utility Class Library
Package java.util contains miscellaneous utility classes, including generic
data structures, settable bits class, time, date, string manipulation, 
random number generation, system properties, notification, and enumeration
of data structures.

. Abstract Window Toolkit Library
Package java.awt provides user interface features such as windows, dialog 
boxes, buttons, checkboxes, lists, menus, scrollbars and text fields. 
It is said to be `Abstract` because it is device and operating system
independent - much to the irritation of some programmers who take their
revenge by inventing other meanings for the acronym.
.See AWT
below and
. Applets
Package java.applet enables construction of applets. It also provides 
information about an applet's parent document, about other applets in that
document, and enables an applet to play audio.
See
.See Applet
below and
. Network Interface Class Library
Package java.net network support, including URLs, TCP sockets, UDP sockets,
IP addresses and a binary-to-text converter.
. Images - Audio and Visual
Package java.image is for managing image data, such as the setting the 
color model, cropping, color filtering, setting pixel values and grabbing 
snapshots.
.Close.Box

. Road_works_ahead
Two question marks `??` 
.See 1_below
indicate that I haven't found the data yet.
If you have found the answer in any offical documentation please
send it to dick@csci.csusb.edu where it will be incorporated with 
an acknowledgement.

These are working notes and are being revised daily.  Again I am
open to corrections and improvements.
. Data Types
.See http://www/dick/samples/java.semantics.html

.Open Object Hierarchy
.Open Object
.Box
	For all `C`:Class, `ob`:Object, ob instanceof C::Boolean.
	Object()::constructor.
	methods: clone() equals() finalize() getClass() hashCode() notify() notifyAll() toString() wait(long) wait(long,int) wait()

. System
.Box
public final class System extends Object
in package java.lang.System

This provides a system-independent model of the operating system.
It includes the standard input and output streams for example. 
The standard input streams are
used for reading character data.  The standard output streams are used for
printing. For example:
.As_is 		System.out.println("Hello World!");

The System Class represents a single and predefined `real` object.
So it cannot have objects of type System(instances)
Nor can it be subclassed.
. System Variables
err::=`Standard Error Reporting Stream`::PrintStream.
.See PrintStream
out::=`Standard Output stream`:: PrintStream.
.See PrintStream
in::=`Standard Input stream`::InputStream.
.See InputStream
and
.See DataInputStream
.Open System Methods
arraycopy(Object, int, Object, int, int)::=` Copies an array from the source array, beginning at the specified position, to the specified position of the destination array`.
exit(int)::= `Exits the virtual machine with an exit code`.
.See Array Copy
currentTimeMillis()::= `Returns the current time in milliseconds GMT since the epoch (00:00:00 UTC, January 1, 1970)`.
See Also
.See Date
gc()::= `Runs the garbage collector`.
getProperties()::= `Gets the System properties`.
getProperty(String)::= `Gets the System property indicated by the specified key`.
getProperty(String, String)::= `Gets the System property indicated by the specified key and def`.
getSecurityManager()::= `Gets the system security interface`.
load(String)::= `Loads a dynamic library, given a complete path name`.
loadLibrary(String)::= `Loads a dynamic library with the specified library name`.
runFinalization()::= `Runs the finalization methods of any objects pending finalization`.
setProperties(Properties)::= `Sets the System properties to the specified properties`.
setSecurityManager(SecurityManager)::= `Sets the System security`.

. Array Copy
.Box
.As_is  public static void arraycopy(Object from_source, int from_source_position,
.As_is                               Object to_destination, int to_destination_position,
.As_is                               int length)
Precondition: Both arrays exist and have space for at least `length` objects.

Postcondition: First `length` Objects in the second array equal those in first array.

Invariant: The first array.
.Close.Box
.Close System Methods
.Close.Box
. Color
.Box
public final class java.awt.Color extends java,lang.Object
.See http://java.sun.com/j2se/1.4.2/docs/api/java/awt/Color.html
old
.See http://java.sun.com/j2se/1.5.0/docs/api/java/awt/Color.html
coming
	colors::={ black, blue, cyan,darkGray, gray, green, lightGray, magenta, orange, pink, red, white, yellow}.
	Color(float red, float green, float blue)::constructor.
	Color(int red, int green, int blue)::constructor.
	Color(int rgb)::constructor.
	color.getBlue()::int, gets commponent of color.
	color.getGreen()::int, gets one component of color.
	color.getRed()::int, gets one component of color.
 ...
.Close.Box
. PrintStream
.Box
public class PrintStream  extends Object
 println(String)
.Close.Box
. InputStream
.Box
public class InputStream  extends Object
(For example the standard input (System.in)
.See in
)
An abstract class representing an input stream of bytes. All InputStreams are based on this class.
	InputStream(), available(), close(), mark(int), markSupported(), read(), read(byte[]), read(byte[], int, int), reset(), skip(long)

. FilterInputStream
.Box
. DataInputStream
.Box
By creating one of these from an unformatted input stream
.See InputStream
you can attempt to read in simple data types from the resulting stream.
DataInputStream(InputStream in)::=`Creates a new DataInputStream`.
For S:DataInputStream, S.readLine()::String=`returns a String copy of the line`.
For S:DataInputStream, S.readFully(byte[] b)::`reads until blocked into b`.
For S:DataInputStream, X:{ Boolean, Byte, Char, Double, Float, Long, Short, UTF, unsignedByte, unsignedShort},S.read`X`()::`X`=`Reads and returns an X`.
.Close.Box
.Close.Box
.Close.Box
. Array
.Box
For each class there is an associated class of arrays.
 An array has a
set of elements of the same class number from 0 to some fixed length. The
elements of array `a` are written `a`[0], `a`[1], . . . , `a`[`a`.length-1].
 Arrays have a fixed length once created.  This is accessable as an field
named `length` of each array:
length_of_array_a::= `a`.length.

Vectors
.See http://java.sun.com/j2se/1.4.2/docs/api/java/util/Vector.html
(1.4.2), 
.See http://java.sun.com/j2se/1.5.0/docs/api/java/util/Vector.html
are like arrays but can expand when needed.  

For all `C`:Classes, A:Classes=array_of_C, `i`:identifier, `e`:expression, `a`:array_of_C, `v`:`array_of_C_variable`, `ec`:`C expression`,

	`C` []::Classes=`class of arrays of objects of class C`::=`A`,

	`C` [] `i`::declaration=`declare_an_array_of_C`,

	`C` `i` []::declaration=`declare_an_array_of_C`,

	`v`=`a`::expression(`A`)=`afterwards v refers to array a`,

	`v`[`e`]=`ec`::expression(`C`)=`afterwards the e.th element of v has value ec but no other elements of v have been effected`,

	new `C` [ `e` ]::expression(`A`)=`a new array of e C's`,

	`a`.length::int=`number of items of class C in array a`,

	`a`[`e`]::expression(`C`)=`the e.th element of array a`,

	(`C`[])`ec`::expression(`A`)=`an array with element ec of length 1`??
.See 1_below

For all `A`:Classes, `B`:subclasses(`A`), `B`[] in subclasses(`A`[]).

For arrays of characters see character strings
.See String and StringBuffer

For arrays indexed by general objects see hash tables
.See HashTable
.Close.Box
. String and StringBuffer
.Box
(String): A general class of objects to represent character Strings. Strings are
constant, their values cannot be changed after creation.
.See http://java.sun.com/j2se/1.4.2/docs/api/java/lang/String.html
.See http://java.sun.com/j2se/1.5.0/docs/api/java/lang/String.html
	literal::= double_quotes string double_quotes.
	infix::={"+"}. -- concatenation.  -- hence "+="
	String()::=`construct new empty string`.
	String(String), String(char[]), String(char[],int,int), String(byte[], int ,int,int), String(byte[], int), String(StringBuffer)::=`Construct new String copying various data`.
	charAt(int)::=`character at (_)`.
	compareTo(String)::int=`lexographic comparison return <0 if <, 0 if equal and >0 if >`.  See C.strcmp.
	concat(String)::=`Place (_) at end of this String`.
	copyValueOf, endsWith, hashCode(String), intern,
	equals(String)::boolean=`This string is the same as (_)`.
	equalsIgnoreCase(String)::boolean,
	getBytes(int,int,byte[],int)::=`Copy into (3rd)`,
	getChars(int,int,char[],int)::=`copies chars into (3rd)`.
	indexOf(...)::int=`position of first matching (_) in this string`.
	lastIndexOf(...)::int=`position of last matching (_) in this string`.
	length()::int=`number of chars/bytes in string`.
	...
	substring(int), substring(int,int)::String=`substrings of this string`.
	toCharArray(), toLowerCase(), toString, toUpperCase,
	trim()::=`remove leading and trailing whitespace`.
	valueOf(...)::=`String object cantain representation of (_)`.
.Box
(StringBuffer): This Class is a growable buffer for characters. It is 
mainly used to create Strings.  But can append any kind of Object which is 
??
.See 1_below
converted into a sequence of characters before being added to the buffer,
`StringBuffer(...)` creates Strings and `StringBuffer append(Object obj)` adds an object to the end of this buffer and returns the StringBuffer itself
.See http://java.sun.com/j2se/1.4.2/docs/api/java/lang/StringBuffer.html
.See http://java.sun.com/j2se/1.5.0/docs/api/java/lang/StringBuffer.html
	append(...)::=`Put (_) after the last character of this string`.
	capacity()::=`capcity of theis string`.
	ensureCapacity(int)::=`Make sure room for (_) chars`.
	charAt(), getChars(),
	insert(int, X)::=`Inserts an X into the buffer`.
	length()::int=`number chars in this string buffer`.
	setCharAt(int, char)::=`change this string's (1st) char to (2nd)`.
	setLength(int::=`Set length to (_) chars`,
	toString()::=`converstbuffered data to String`.
.Close.Box
.Close.Box
. Dictionary
.Box
The Dictionary class is the abstract 
.See http://www/dic/samples/java.semantics.html#abstract
parent of Hashtable, which maps
keys to values. Any object can be used as a key and/or value. Any
Object has a `hashCode(_)`.
	Dictionary() elements() get(Object) isEmpty() keys() put(Object, Object) remove(Object) size()
.Close.Box
. Vector
.Box
.See http://java.sun.com/j2se/1.4.2/docs/api/java/util/Vector.html
.See http://java.sun.com/j2se/1.5.0/docs/api/java/util/Vector.html
. Stack
Stacks
.See http://java.sun.com/j2se/1.4.2/docs/api/java/util/Stack.html
.See http://java.sun.com/j2se/1.5.0/docs/api/java/util/Stack.html
are Vectors that can accessed at only one end - the "top" - by
`push()` and `pop()` operations.
.Close.Box
. Number
.Box
Number
.See http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Number.html
.See http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Number.html
is an abstract superclass for numeric scalar types, like (Integer):fixed(16.bits, signed),
(Long):fixed(32.bits, signed),
(Float):floating_point(16.bits,IEEE) and (Double):(32,bits, IEEE): are subclasses of Number
.See http://www/dick/samples/java.semantics.html#numeric.
Each of these provides a method for extracting the basic data type from the object: (int intValue(Integer), double doubleValue(Double), float floatValue(Float), long longValue(Long)), and a constructor for making
the Object from its data ( Integer(int), Long(long),....).
.Close.Box
. Math
.Box
(Math Constants): E, PI
(Math Functions): abs acos asin atan atan2 ceil cos exp floor log max min pow randon rint round sin sqrt tan

Warning: the behavior specified for mathematical functions is implementation
dependent.  For example they are supposed to
throw an exception when the answer is not a number (eg sqrt(-1)). However
they have been implemented as calling the standard C library functions
and so return Double.NaN(Double's IEEE Not-a-Number value).
.Close.Box
. Class
.Box
	forName(String) getClassLoader() getInterfaces() getName() 
	getSuperclass() isInterface() newInstance() toString()
.Close.Box
.Open AWT
.Box AWT Component
	action(Event,Object) addNotify()
	bounds()
	checkImage(Image, ImageObserver) checkImage(Image, int, int, ImageObserver) createImage(int, int)
	deliverEvent(Event) disable()
	enable() enable(boolean)
getBackground() getColorModel() getFont() getFontMetrics(Font) getForeground() getGraphics() getParent() getPeer() getToolkit() gotFocus(Event, Object)
	handleEvent(Event) hide()
	imageUpdate(Image, int, int, int, int, int) inside(int, int) invalidate() isEnabled() isShowing() isValid() isVisible()
	keyDown(Event, int) keyUp(Event, int)
	layout() list() list(PrintStream) list(PrintStream, int) locate(int, int) location() lostFocus(Event, Object)
	minimumSize() mouseDown(Event, int, int) mouseDrag(Event, int, int) mouseEnter(Event, int, int) mouseExit(Event, int, int) mouseMove(Event, int, int) mouseUp(Event, int, int) move(int, int)
	nextFocus()
	paint(Graphics) paintAll(Graphics) paramString() postEvent(Event) preferredSize() prepareImage(Image, ImageObserver) prepareImage(Image, int, int, ImageObserver) print(Graphics) printAll(Graphics)
	removeNotify() repaint() repaint(long) repaint(int, int, int, int) repaint(long, int, int, int, int) requestFocus() reshape(int, int, int, int) resize(int, int) resize(Dimension)
	setBackground(Color) setFont(Font) setForeground(Color) show() show(boolean) size()
	toString()
	update(Graphics)
	validate()

.Box AWT Container
  add(Component) add(Component, int) add(String, Component) addNotify() 
	countComponents()
 deliverEvent(Event) getComponent(int) 
	getComponents() getLayout()
 insets()
 layout() list(PrintStream, int) locate(int, int) minimumSize()
 paintComponents(Graphics) paramString() preferredSize() printComponents(Graphics) 
	remove(Component) removeAll() removeNotify() 
	setLayout(LayoutManager)
 validate()
.Box AWT Panel
	Panel() addNotify()
.Close AWT
. Applet
.Box
	Applet()
 destroy()
 getAppletContext() getAppletInfo() 
	getAudioClip(URL) getAudioClip(URL, String) getDocumentBase() getImage(URL) getImage(URL, String) getParameter(String) getParameterInfo()
 init() isActive()
 play(URL) play(URL, String) 
	resize(int, int) resize(Dimension)
 setStub(AppletStub) showStatus(String) start() stop()
.Close.Box
.Close.Box
.Close.Box
.Close.Box

.Close.Box 
.Close Object
.Close Object Hierarchy

.Close The Predefined Classes in Java
.Open End Notes
(1_below): Indicates something that I think is true but have not been able to
check please sen mail to dick@csci.csusb.edu to either confirm or deny
the opeinion expressed thereafter.

.Close End Notes