Java Identifiers

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Java Identifiers

A name in java program is called identifier, which can be used for identification purpose.
It can be method name, variable name, class name or label name.

Example

Rules for defining java identifiers:-

The only allow characters in java is identifer are a to z , A to Z, 0 to 9 , _ and $ . By mistake if you are using any other character you will get compile time error.
example: int total_number = 7;
Identifiers can’t start with digits.
example: int 123total = 25;
example: int total123 = 25;
Java identifier are case sensitive offcourse java language itself is treated as case sensitive programming language.

Example

public class Test {
  public static void main(String[] args) {
   int number = 10;
   int Number = 20;
   int NUMBER = 30;
   int NUMber = 40;
  }
}

Note:- All variables are different. We can differentiate with case.

There is no length limit for java identifer but it is not recommended to take too lengthy identifer.
example: int abcdefghijklmnopqrst = 7;
We can’t use reserved words or keyword as identifer.
example: int else = 25;
All predefined java class name and interface name we can use as identifier.

Example

public class Test {
  public static void main(String[] args) {
   int String = 888;
   System.out.println(String);
  }
}

Example

public class Test {
  public static void main(String[] args) {
   int Runnable = 888;
   System.out.println(Runnable);
  }
}

Note:- Even it is valid but it not good a good programming practice because it reduces readability and creates confusion.

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