Java fundamentals 2
- 2. Topics to be covered Difference between object-oriented programming and procedural programming Advantages of OOP Introduction to Java Building a Java class
- 3. Object-Oriented Programming (OOP) vs. Top-Down (Procedural) Programming OO approach System is defined as a collection of objects that work together to accomplish tasks Objects carry out actions when asked Each object maintains its own data Procedural approach System is defined as a set of procedures that interact with data Data is maintained separately from procedures
- 5. Advantages of Object-Oriented System Development Objects are more natural Reuse Classes and objects can be invented once and used many times during analysis, design, and programming Do not need source code for reused class, simply need to know interface
- 7. Introducing Java Released mid 1995 by Sun Microsystems Designed to be: A powerful, full-featured, pure OO development language Easy to learn - syntax is similar to C++ Platform independent Support development of applications for networked environment Ideal for Web-based applications
- 8. Introducing Java Powerful Class library Hundreds of prewritten classes Provide methods to accomplish various tasks OO Implements OO concepts described in Ch. 1 Encourages good software design Reduces debugging and maintenance
- 9. Introducing Java Portability Programs can be written and compiled once, then run on different platforms Important for internet applications (applets) Achieved by using: Bytecode Produced when a Java program is compiled Interpreter (Java Virtual Machine – JVM) Execution environment for bytecode on each platform
- 10. Building a Java Class Each source code file defines a class Class Hello.class File Hello.java Class header Describes class contained in source code file Keywords: public Indicates class has public availability class Indicates line of code is a class header
- 11. Building a Java Class Identifiers Name of a class, method, or variable Can be any length Can include any character except a space Must begin with a letter of the alphabet, a dollar sign ($), or the underscore (_) character Java is case sensitive Public isn’t the same as public
- 12. Block of code Used to group statements Delineated by open curly brace ({) and closed curly brace (}) All code in Java is enclosed in a single block of code, which can contain additional blocks