Java Coding Style Rules

Align all curly braces vertically to allow easy visual matching.
Use four (4) spaces for each indentation.
Indent all statements contained within compound statements (if, for, while, {}, etc).
Use meaningful names for variables, parameters, subprograms, and classes. (You may use simple names like i, c, s, or f for general integers, characters, strings, or floats respectively.)
Define and use names for all constants, e.g., PI instead of 3.14159, and BUF_SIZE instead of 1024.
Give an appropriate visibility modifier in front of every member definition, either public, private, or protected. Only use package scope when you know it is appropriate.

Use the following conventions for letter-case of identifiers:

Identifier	Convention	Examples
class names	capitalize first word, capitalize all other words (no underscores)	Circle, FilledCircle, ShadedFilledCircle
class member names	lowercase first word, capitalize all other words (no underscores)	draw(), drawLine(), centerX, centerY, radius
function names	lowercase first word, capitalize all other words (no underscores)	findIndex(), factorial(), toLowerCase(), isUpperCase()
named constants	all caps, use underscores to separate words	PI, MAX_BUFFER_SIZE

Use whitespace around every binary operator (e.g, x + y instead of x+y) and around function arguments (e.g, put( x, y ) instead of put(x,y)).
Keep subprograms simple. At most five simple statements or one compound statement and two simple statements.
Keep compound statements simple. At most three simple statements per statement list.
Avoid over parenthesization, e.g, return x + 1; instead of return (x + 1);
Comment each class, each method, and each class variable (describing it's purpose) using a form similar to the example at the very end. (Note I only commented a few members to avoid cluttering up the Class example.)

Examples of statments

simple if/else

     if ( x < y )
         y = 0;
     else
         x = 1;

cascaded if/else

     if ( var1 < var2 )
     {    
         var1 = ...;
         var2 = ...;
           ...
     }
     else if ( var1 == var2 )
     {
         var1 = ...;
         var2 = ...;
         ...
     }
     else
     {        
         var1 = ...;
         var2 = ...;
           ...
     }

loop statements


     for ( int i = 0; i < MAX_VAL; i++ )
     {
         ...
         ...
     }

     while ( !cin.eof() )
     {
         cin.get( ch );
         cout.put( ch );
     }

     do // read the first line (including the newline) only
     {
         cin.get( ch );
         cout.put( ch );
     } while ( ch != '\n' );

switch statements


     switch ( factorial( i ) )
     {
         case 1:
         case 3:
         case 5:
             cout << "It's odd!\n";
             break;
         case 2:
         case 4:
         case 6:
             cout << "It's even!\n";
             break;
         default:
             cout << "It's less than 1 or greater than 6!\n";
             break;
      }

Examples of Class Definitions


     import java.awt.*;

     /*
         class Triangle defines a two dimmensional Triangle
     */

     class Triangle
     {

         // the x,y coordinates of the origin of this Triangle

         private int x, y;

         // draws this Triangle on the display

         public void draw()
         {
            // ...
         }

         // inverts this Triangle along a horizontal line

         public void flip()
         {
            // ...
         }

         // rotates this Triangle by number of degrees specified by angle

         public void rotate( int angle )
         {
            // ...
         }

     }

Examples of REALLY BAD commenting

All the following comments are poor. Either they state the obvious about the programming language (typical from programmers just learning the language), or they don't add any information about the item they are commenting and the program would actually be more readable if they were deleted. The final offense is pointing out that a particular close brace matches some open brace. If you find yourself needing this, either you aren't aligning your braces properly, or your code is getting too complex.


     /*
        This is a class defintion for Shape.
     */
     class Shape
     {
     public:
         // These are abstract methods
         // draws shape
         abstract void draw();
         // flips shape
         abstract void flip();
         // rotates shape
         abstract void rotate( int angle );
     } // end of Shape

     // A Point class
     class Point
     {
         // Two integers
         private int x, y;
         // a constructor
         public Point( int newX, int newY ) 
         {
             // initialize x and y
             x = newX;
             y = newY;
         } // end of Point
     }
    
     class Rectangle
         extends Shape // Rectangle extends a Shape
     {
         // some private members
         private Point tl;
         private Point br;
         private int angle;
     
          // the public members
         public Rectangle() // constructor
         {
         }
         // ...
         // some member functions
         void draw()
         {
            // ...
         }
         void flip()
         {
            if ( x != y )
            {
                swap( x, y ); // swap the values of x and y 
                flip(); // flip again
            } // end if
         } // end flip()
         void rotate( int angle )
         {
         }
         float area()
         {
         }
     } // end Rectangle