JAVA

Oracle has two products that implement Java Platform Standard Edition (Java SE) 8: Java SE Development Kit (JDK) 8 and Java SE Runtime Environment (JRE) 8. JDK 8 is a superset of JRE 8, and contains everything that is in JRE 8, plus tools such as the compilers and debuggers necessary for developing applets and applications. JRE 8 provides the libraries, the Java Virtual Machine (JVM), and other components to run applets and applications written in the Java programming language. Note that the JRE includes components not required by the Java SE specification, including both standard and non-standard Java components. The following conceptual diagram illustrates the components of Oracle's Java SE products: Description of Java Conceptual Diagram

1990 Oak (interactive television, big failure) 1994 Java (for the Internet) Main feature: "Write Once, Run Any Where" => wrap the operating system so they all look the same Designed for A fresh start (no backward compatibility) “Pure” OOP: C++ Syntax, Smalltalk style Improvements over C++ much harder to write a bad program  Internet programming Very hard to create a virus  Run in a web browser (and at the server) There is a speed issue (from Java 1.3 and up much better) C# Microsoft's “Java-Killer” project release 2001 Language very similar to Java   Commen-Language Runtime (CLR) supports 30+ languages  

Polymorphism: One piece of code works with all shape objects. Dynamic binding: How polymorphism is implemented Take previous Shape class hierarchy  remove inheritance  remove general and abstract class Shape 

Generalization creates a concept with a broader scope. Specialization creates a concept with a narrower scope. Reusing the interface!  Inheritance: get the interface from the general class. Objects related by inheritance are all of the same type.

Idea: make new objects by combining existing objects. Reusing the implementation!  An aggregation consists of a number of (sub-)concepts which collectively is considered a new concept. A decomposition splits a single concept into a number of (sub-)concepts.