module 1 - executing your first java application

8/13/2019 Module 1 - Executing Your First Java Application

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Java Programming Language


SL-275-SE6


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Module 1

Executing Your First Java Application


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Java Programming Language Module 1, slide 2 of 24Copyright 2007 Sun Microsystems, Inc. All Rights Reserved. Sun Services, Revision G

Objectives

Examine the Java Development Kit (JDK) software

Examine Java application loading and executing Create a simple Java application


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Examining the JDK Software

The JDK contains components to perform the following tasks:

Develop Java technology applications Deploy Java technology applications

Execute Java technology applications

JDK


Tools and Tools API

Java SE Libraries

Deployment Technologies

Platform Specific JVMs

Applicationdevelopment

Applicationdeployment

Applicationexecution


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Components of the JDK

The Java programming language

Tools and tools API Deployment technologies

Java Platform, Standard Edition (Java SE) libraries

Java Virtual Machine (JVM)Strictly speaking the Java programming language is not acomponent of the JDK software. Nevertheless, for thepurposes of providing a more complete discussion, it is

treated as a pseudo component.

Download URL:http://java.sun.com/javase/downloads/index.jsp


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Examining the JDK Support for DevelopingJava Technology Applications

The Java programming language The JDK tools

The JDK libraries


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The Java Programming Language

The Java programming language is a general-purpose,concurrent, strongly typed, class-based object-orientedlanguage.

The Java programming language is defined by theJavalanguage specification.

The primary building block of a Java technologyapplication is aclass.


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Example of a Java Technology Class

1 package trader;2 import java.io.Serializable;

3 public class Stock implements Serializable {4 private String symbol;5 private float price;67 public Stock(String symbol, float price){8 this.symbol = symbol;

9 this.price = price;10 }1112 // Methods to return the private values of this object13 public String getSymbol() {14 return symbol;15 }1617 public float getPrice() {18 return price;19 }


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Example of a Java Technology Class

2021 public void setPrice(float newPrice) {

22 price = newPrice;23 }2425 public String toString() {26 return "Stock: " + symbol + " " + price;27 }

28 }


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The JDK Tools and Tools API


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Basic Tools

Tool Name Function

javac The compiler for the Java programming languagejava The launcher for Java technology applications

jdb The Java debugger

javadoc The API document generator

jar Java Archive (JAR) file creator and management tool


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Advanced Tools

Tool Category Comments

Security tools Implement security policies in applicationsInternationalizationtools

Enable applications to be localized

Remote methodinvocation (RMI) tools

Create (network) distributed applications

Common object requestbroker architecture(CORBA) tools

Create network applications that are based on CORBAtechnology

Java deployment tools Support application deployment

Java Plug-in tools Provide utilities for use with the Java Plug-in

Java web start tools Used with Java web start technology


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Advanced Tools

Tool Category Comments

Java Monitoring andManagement (JMX)console

Used in conjunction with JMX technology

Java web services tools Support Java web service application development

Experimental tools Might not be available with future releases of the JavaSE JDK


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JDK Libraries


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JDK Libraries

Library Name Sample Classes in Library

java.lang Enum, Float, String, Objectjava.util ArrayList, Calendar, Date

java.io File, Reader, Writer

java.math BigDecimal, BigInteger

java.text DateFormat, Collatorjavax.crypto Cipher, KeyGenerator

java.net Socket, URL, InetAddress

java.sql ResultSet, Date, Timestamp

javax.swing JFrame, JPanel

javax.xml.parsers DocumentBuilder, SAXParser


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Java Technology APIDocumentation


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JDK Deployment Technologies


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The Java Virtual Machine (JVM)

What is a JVMimplementation?

Are JVM implementations platform dependent?

Are Java technology applications platform dependent?

What is a Java Hotspot JVM implementation?

What is a Java Hotspot client JVM implementation?

What is a Java Hotspot server JVM implementation?

Java Technology Application

JVM

OS

Hardware Platform


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The JVM: Supported Platforms


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The Java Runtime Environment (JRE)


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Examining Java Technology ApplicationLoading and Execution

Compile

TestGreeting.java

TestGreeting.class

javac

Runtime

Classloader

Bytecodeverifier

Hotspot Execution Engine

Hardware

Load fromhard disk,network,

orother

source

java


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A Simple Java Application

1 //2 // Sample "Hello World" application3 //4 public class TestGreeting {5 public static void main (String[] args) {6 Greeting hello = new Greeting();7 hello.greet();8 }

9 }

1 public class Greeting {2 public void greet() {3 System.out.println("hi");4 }

5 }6

javac TestGreeting.java

java TestGreeting


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Troubleshooting: Compile-Time Errors

javac: Command not found

Greeting.java:4:cannot resolve symbolsymbol : method printl (java.lang.String)location: class java.io.PrintStreamSystem.out.printl("hi");

^

Class and file naming

Class count


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Troubleshooting: Run-Time Errors

Can't find class TestGreeting

Exception in thread "main"java.lang.NoSuchMethodError: main


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Compiling and Running

JVM

Compile

TestGreeting.java

TestGreeting.class

javac

Greeting.java

Greeting.class

Also compiles

Run

time

Also loads

UNIX

JVM

DOS

JVMJavaOS

Can run on multiple platforms

module 1 - executing your first java application

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