01- Java Introdcution

Java is a computer programming language, that is concurrent, class based, object oriented. 
It is indented to let programmers Write once, run everywhere, that compiledd Java code can run on multiple platforms.

Oracle implementation is packaged into two differnt distributions.
  Java Runtime Enviornment 
  Java Development Kit
  
 Garabage Collection
 Java uses an automatic garbage collector to manage memory in the object lifecycle.
 The programmers determine when objects are created, and the java runtime is responsible for recovering the memory
 once objects are no longer in use.  once no references to an object remain, the unreachable memory becomes eligible to be freed 
 automatically by the garbage collector.
 
 The traditional Hello world program in Java
 
 public class HelloWorld{
    public static void main(String[] args){
      System.out.println("Hello World");
    }
 }
 
 
 Java Class file 
 01. Java source files must be named after the public class they contain, appending the suffix .java.(HelloWorld.Java)
 02. It must be first compiled into bytecode using a Java compiler,producing a file named HelloWorld.class only then it can be executed or launched.
 03. The Java source file contains only one public class but it can conatin multiple classes with other than the public access and any number of 
      public inner class.
 04. when the source file contains multiple classes, make one class public and name the source file with that public class name.