- 3 parts universal to Java programs
- comments
  - help programmers understand program
  - state purpose of program
  - explain meaning of code
  - 3 comment types
    - comment markers syntax:
      - start: /*
      - end :*/
    - single-line comment extends from // to end of line
    - javadoc comments covered later
  - computer ignores
  - not necessary for execution
  - important for documentation
    - changes always made
    - often by somebody else
  - particular uses
    - header
      - beginning of program/method
      - describe program/method
    - explain code w/ ambiguous purpose
    - note modifications
    - id/summarize code block
    - disable sections of code during testing
- import 
  - use pre-defined classes whenever possible
  - group classes into packages
  - java comes w/ many packages
  - use class from package
    - syntax: <package name>.<class name>
    - dot notation
    - fully qualified name
  - hierarchy of packages
    - package includes subpackages
    - multiple dots
  - use import to avoid fully qualified name
  - allows to just use class name
  - asterisk to import all classes in a package
    - syntax: import <package name>.*;
    - conventional (as opposed to importing each class)
  - doesn't copy classes into program
- class declaration
  - syntax:

    class <class name> {
    
        <class member declarations>

    }

  - "class" reserved word
  - class member: data val or method
  - every program must include at least one
  - use name of main class + "application" to refer to whole application
  - java automatically executes main method of main class first
  - method declaration
    - syntax:

      <modifiers> <return type> <method name> (<parameters>) {

          <method body>

      }

    - modifiers: state which kind of method (there are many)
    - return type: states type of data value returned by method
  - use program template for now
  - completely different programs can be created readily by using dif objs

Quick Check:
1. comments, import statements, class declarations
2. a main method
3. The comments are green, between /* and */; the import statement is the line "import javabook.*;", and the class declaration runs from "class Ch2FunTime {" to the end of the code.
4. They import different packages and use different classes.  Ch2Sample1 actually uses more methods.
5. This arrow line is meant to be dotted.

    _________________
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   | Ch2MyWebBrowser |
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   |_________________|
           
           |

           |

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    _______\/________
   |                 |
   | Ch2MyWebBrowser |
   |                 |
   |                 |
   |_________________|