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JAVA training-course-navi-mumbai-JAVA-course-provider-navi-mumbaiVibrant Technologies
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1.LECTURE ON OVERVIEW OF JAVA Topics 1.What is java 2.History of Java 3.Versions Of java 4.Tool to write java programs 5.How Java program Run 6.First Java Program 7.Discription of Java Program
How Java Program Run • Java program, use a compiler that reads the statements in the program and translates them into a machine independent format called bytecode. • These instructions, called bytecodes, are the same for any computer / operating system. • The compiled Java code (resulting byte code) will be executed at run time. • Some Definitions For Java Programs • 1. Unicode- Unicodeprovides a unique number for every character,no matter what the platform, program and language. • 2.Bytecode- highlyoptimized set ofinstructions designed to be executed by the JVM in any platform. • 3. Java Virtual Machine- itinterpret .java file andconverted to bytecode i.e. .class file. • 4.Just in Time Compiler- complies bytecode intoexecutable code in real time
Flow of JAVA Program Character-- for exam.(\b\t) Demo.java Unicode(\u0008 \u0009) JVM( Java Virtual Machine)javac Demo.java interpreter Bytecode( .class File) Demo.class JIT( Just in Time Compiler) java Demo compiler Final output
What is Java? 1.Java is a object oriented programming language and also platform first released by Sun Microsystems in 1995. 2. It is intended to let application developers "write once, run anywhere" (WORA), meaning that code that runs on one platform does not need to be recompiled to run on another 3. James Gosling Mike Sheridan, and PatrickNaughton are the creators and developers of java language 4. In 2009-10 Oracle Corporation takes acquisition of Sun Microsystems. 5. Java software runs on everything from laptops to data centers ,game consoles to scientific supercomputers . There are 930 million Java Runtime Environment downloads each year and 3 billion mobile phones run Java.
Tools(IDE) To Write Java Programs 1.Editors. Editors are simpler: they generally highlight the Java syntax, indent for developer, balance y parentheses and braces, and let compile from within the editor. But that's about it: they don't write code, integrate tightly with the compiler or app server, or have graphical Java development tools. 2.IDEs.IDEs i.e. Integrated development environment are more complex: most of them have visual Java development tools, tight integration with the compiler or application server, and may include tools for debugging, refactoring, version control, and so forth. 3.Some of the IDEs for java are Eclipse, NetBeans, BlueJ,Jcreator,IntelliJ IDEA Borland Jbuilder etc… .
First Java Programs Demo.java public final class Demo { System.out.println(“ demo class”); } Step for Saving, compiling and Running a Java Program • Step 1: Save the program With .java Extension. • Step 2: Compile the file from DOS prompt by typing javac <filename>. • Step 3: Successful Compilation, results in creation of .class containing byte code • Step 4: Execute the file by typing java <filename without extension>
Description Of Java Program public static void main(String args[]) { System.out.println(“hello”); } Contents Of Java Program public- access specifier publicly static-allow main() to be called without instantiate a particular instance of the class void- does not return a value main()- called by JVM for interpretation String args[]-array of instance of class String objects of type String store character Strings. args[] receives any command –line arguments at runtime System-predefined class in java.lang pkg. out- -output stream connected to the console. println()- method to print line , string provided as argument