2. Basics of Java
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This document provides an overview of the basics of Java. It discusses that Java is an object-oriented programming language derived from C and C++. It was originally developed by Sun Microsystems in 1991 under the name Oak but was renamed to Java in 1995. The document outlines the history and development of Java, and describes how Java programs can create both applications and applets. It also summarizes some of the key differences between Java and C++. Finally, it provides a high-level overview of the main features of Java including being simple, object-oriented, platform independent, secure, robust, architecture neutral, portable, dynamic, interpreted, high performance, multi-threaded, and distributed.
2. Basics of Java
- 1. Basics of JavaBasics of Java By Nilesh Dalvi Lecturer, Patkar-Varde College.Lecturer, Patkar-Varde College. http://www.slideshare.net/nileshdalvi01 Java and Data StructuresJava and Data Structures
- 2. Introduction • Java is a object-oriented programming language. • Related to C++, which is an offspring of C-Language. • Much of the characteristics of Java inherited from C-Language & C++. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W). C-Language C++ Java Syntax Oops features
- 3. History of Java • General purpose object-oriented language developed by sun microsystems in 1991. • It is initially called ‘oak’, was renamed as ‘Java’ in 1995. • Originally designed to develop software for consumers electronic devices like toasters, TVs, etc. • First language that is not tied to any particular H/W or OS • Java is platform-neutral language. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 4. Java applets and Application • Used to create two types of programs: Applications and Applets. • Application: program that runs on your computer, under the os of that computer. • Applet: application designed to be transmitted over the internet and executed by a Java-compatible web browser. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 5. Difference between C++ and Java • Java does not support operator overloading • Java does not have template classes as in C++. • Java does not support multiple inheritance of classes. Accomplished by “interfaces” • Java does not support global variables, every variable & method is declared within a class. • Java does not use pointers. • Java has replaced destructor function with a finalize() method. • There are no header files in java. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 6. Java Features Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W). Simpl e Object- Oriented Platform-independent Secured Robust Architecture-neutral Portable Dynamic Interpreted High Performance Multi-threaded Distributed
- 7. Java Features Simple: • According to Sun, Java is simple because: – Syntax is based on C and C++ (so easier for programmers to learn it after C++). – Removed many confusing and/or rarely-used features e.g., explicit pointers, operator overloading etc. – No need to remove unreferenced objects because there is Automatic Garbage Collection in java. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 8. Java Features Object-Oriented: • Object-oriented programming(OOPs) is a methodology that simplify software development and maintenance by providing some rules. • Basic concepts of OOPs are: – Classes and Objects – Inheritance – Polymorphism – Abstraction – Encapsulation Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 9. Java Features Platform-independent • A platform is the hardware or software environment in which a programs runs. • Java platforms has to components – JVM (Java Virtual Machine) – Java application programming Interface(API) • Java programs can be easily moved from one computer system to another, any where any time, changes in OS, processors and system resources will not force any changes in java programs. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 10. Java Features Platform-independent Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 11. Java Features Secure: • With java secure features it enable us to develop virus free, temper free system. • Java program always runs in Java runtime environment with almost null interaction with system OS, hence it is more secure. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 12. Java Features Robust: • Robust simply means strong. – Java uses strong memory management. – There are lack of pointers that avoids security problem. – There is automatic garbage collection in java. – There is exception handling and type checking mechanism in java. • All these points makes java robust. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 13. Java Features Architecture-neutral : • There is no implementation dependent features • e.g. size of primitive types is set. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 14. Java Features Portable : • Java byte code can be carried to any platform. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 15. Java Features High -Performance: • Java enables performance with the use of just-in- time compiler. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 16. Java Features Distributed: • Java is designed as a distributed language for creating applications on networks. • It has ability to share both data and programs. • This enables multiple programmers at multiple remote locations to collaborate and work together on a single project. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 17. Java Features Multi-threaded: • A thread is like a separate program, executing concurrently. • We can write Java programs that deal with many tasks at once by defining multiple threads. • This means that we need not wait for the application to finish one task before beginning another. • The main advantage of multi-threading is that it shares the same memory. • Threads are important for multi-media, Web applications etc. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 18. Java Features Dynamic: • Java is a dynamic language. • Java is capable of dynamically linking in new class libraries, methods and objects. • Java programs supports functions written in other languages such as C and C++. These functions are known as native methods. • Native methods are linked dynamically at runtime. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 19. Java Features Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W). SimplSimpl ee Object-Object- OrientedOriented Platform-independentPlatform-independent SecuredSecured RobustRobust Architecture-neutralArchitecture-neutral PortablePortable DynamicDynamic InterpretedInterpreted High PerformanceHigh Performance Multi-threadedMulti-threaded DistributedDistributed
- 20. Java Development Kit JDK contains a collections of tools that are used for developing and running Java programs javac (java compiler) – converts source code into java bytecode. java (java interpreter) – An interpreter interpret the class files generated by the javac compiler. jar (archiver) - which packages related class libraries into a single jar file. javadoc - documentation generator, which automatically generates documentation from source code comments (HTML format) jdb (debugger)- Helps to finds errors in our programs javap (disassember) – enables to convert byte code files into a program source code. appletviewer – This tool can be used to run and debug java aaplets without a web browser. javah – Produces header files for use with native methods. Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W).
- 21. JVM Architecture Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W). Java File .class .class .class javac Java compiler Compile-time
- 22. JVM Architecture Nilesh Dalvi, Lecturer@Patkar-Varde College, Goregaon(W). Class Loader Class Segment Heap Segment Stack Segment Native Methods Interface Java Native Libraries Operating System Just In-time Compiler Ram Memory Memory Mgmt Execution Engine Exception Handling .class JRE API JVM
- 23. Q & A