• Coding Standards(CS) and Naming conventions(NC) are suggestions given by sun(Oracle).
  • CS and NC help developers to develop projects with more readability and understandability

Why Coding Standards? 

  • A program is written once , but read many times
    1. During debugging
    2. When adding to the program
    3. When updating the program
    4. When trying to understand the program
  • Anything that makes a program readable and understandable saves lots of time , even in the shot run.

Naming Conventions: 

1.Naming a class:

  • Class name should be "noun", because it represents things
  • Class name should be in title case , means Every word first letter should be capital letter.
  • This is also known as UpperCamelCase.
  • Choose descriptive and simple names.
  • Try to avoid acronyms and abbreviations.

  1. package com.instanceofjava
  2. public JavaDemo{
  4.  }

2.Naming a Variable:

  • Variable name also should be noun, because it represents values.
  • Variable name should be start with small letter. 
  • Use lowerCamelCase.
  • Example: firstName, lastName, age.
  • For final variable all its letters should be capital and words must be connected with "_".
  • Example:  MAX_COUNT, MIN_COUNT.

  1. package com.instanceofjava
  2. public JavaDemo{
  4.  String topicName;
  5.  String post;
  6.  int postNumber;
  7.  final static int MIN_WORDS=300;

  8.  }

3.Naming Method:

  • Method name should be verb because it represents action.
  • Use lowerCamelCase for naming methods
  • Example: setFirstName(), getFirstName(), getLastName().

  1. package com.instanceofjava
  2. public JavaDemo{
  4.  String topicName;
  6. public void setTopicName(String topicName) {
  7. this.topicName=topicName;
  8.  }
  10. public void getTopicName() {
  11. return topicName;
  12.  }
  14.  }

4.Naming a package:

  • All letters should be small 
  • like in java io, util, applet
  • Example com.instanceofjava

  1. package com.instanceofjava
  2. public JavaDemo{
  3.  }
  • If you do not follow all above naming conventions compiler wont any Error or exception.
  • But naming conventions are  useful in project and need to follow.
  • But we need to follow some identifier rules as follows.


  • Identifier is the name of the basic programming elements.
  • class names, methods names , object names and variables names are identifiers
  • If we define a basic program without a name , compiler throws compile time error.
  • Compilation Error : <identifier> expected.
  • if we take a class without name then compile time error will come : Syntax error on token "class", Identifier expected after this token.

  1. package com.instanceofjava
  2. public {   //  Syntax error on token "class", Identifier expected after this token.
  3.  }

Rules in defining identifier:

  • While defining identifier we must follow bellow rules, else it leads to compile time error.

1.Identifier should only contain :

  1. Alphabets(a -z and A-Z)
  2. Digits (0-9)
  3. Special Characters ( _ and $)

2.Identifier should not start with a digit:

  • A digit can be used from second character onwards.
  • Example : 
  • 1strank : throws error
  • No1Rank : works fine

3.Identifier should not contain special characters except "-" and "$":

  • Example : 
  • first_name : works fine
  • first#name : throws error

4.Identifier is case sensitive :

  • identifier is case sensitive
  • For example a and A are different a!=A.

5.keyword cannot be used as user defined identifier :

  • we can not use keywords as our identifiers
  • For example int class; // Syntax error on token "class", invalid VariableDeclarator.


  • we can use predefined class names as identifiers
  • example : int String;
  • There is no limit in identifier length.

Java comments:

  • A description about a basic programming element is called comment.
  • Comments are meant for developer, to understand purpose.

Types of comments:

  • Java supports 3 types of comments
  1. Single line comments  - //
  2. Multiline comments  - /* */
  3. Document comment - /** */

Instance Of Java

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