Download Java Introduction

Java Introduction
劉登榮
Deng-Rung Liu
87/7/15
Outline
 History
 Why Java?
 Java Concept
 Java in Real World
 Language Overview
 Java Performance!?
 Conclusion
History (1/2)
 Consumer electronics technology
 Hardware & Software Difference
 Programming language bottleneck
 New Language Solution
History (2/2)
 Proposed by Sun Microsystem
 For Consumer Electronics
 Not Only For Consumer Electronics
 New Language ? (Updating)
Why Java ? (1/3)
 Language trend (High-Level)
 Object-Oriented world
 Security requirement (Machine & To Yourself)
 Internet hot! (Interactive Document)
Why Java ? (2/3)
 Applications in the OS(Seldom Using
Applications)
 Real World?! Different Platform?! (How to
cross different platform)
 Write-Once-Run-Anywhere ! (Quickly
Development)
 Integrated with new technology
Why Java ? (3/3)
 Distributed computing trend (RMI)
 Backward compatibility (Only Related to Java
Virtual Machine)
 Fit wireless communication (low bandwidth
required)
 Some news!
Java Concept (1/6)
 Java Virtual Machine (JVM)
Java Source
Code
JVM
(Intel)
Intel/
Windows PC
Java
Compiler
JVM
(Sun)
SPARC/
Solaris Workstation
Byte Code
Other Architectures
Supporting JVM
Java Concept (2/6)
 Java Runtime Environment (JRE)
Class loader
& bytecode
verifier
Interpreter
Garbage Collector
awt
io
net
...
Java class libraries
JIT
...
Threads and Synchronization
JVM
Java Concept (3/6)
 100% Object-Oriented Programming
Language
 C-Like grammar
 Different Packages & Interfaces
Java Concept (4/6)
 Relation between JVM & Application
 Interpreter & JIT (Just-In-Time Compiler)
 JDK (Java Development Kit) & JVM
 Java Version
Java Concept (5/6)
 Development Environment
JDK
Visual J++
Symantec Café
 No pointer in Java (Object Reference)
 No memory management mechanism
(Garbage Collector)
Java Concept (6/6)
 Java Native Interface (JNI)
Array of pointers
to JNI functions
Pointer
Per-thread
JNI data
structure
C Language
Function
Pointer
Native method
Pointer
Native method
Pointer
Native method
...
Java in Real World
 IC Card Machine
 Consumer Electronics
 Very small Hand Computer (Java Chip)
 Will be HOT in Consumer Electronics
Language Overview
 Sample Code
Java Defect?! (1/2)
 Hardware interface
 Interpreter language performance
 Java bug!?
 Lack OS support
Java Defect?! (2/2)
 OS attention
 Not popular language for programmer
 Sun Microsystem
Conclusion
 A New Programming Language
 Cross-Platform Implementation
 Java Chip
 Java OS
 Other OS Support
 Project Experience Sharing