Identifiers are just the name of the variables, methods, classes, interfaces etc.
 Each of the above things is identified by their names in the program. 
They are not the thing themselves, they justpoint to the values in the memory. Identifiers follows some rules to be declared:    * Identifiers must be composed of letters, numbers, the underscore _ and     the dollar sign $.       * Identifiers may only begin with a letter, the underscore or a dollar sign.

Identifiers are just the name of the variables, methods, classes, interfaces etc.
 Each of the above things is identified by their names in the program. 
They are not the thing themselves, they justpoint to the values in the memory. Identifiers follows some rules to be declared:    * Identifiers must be composed of letters, numbers, the underscore _ and     the dollar sign $.       * Identifiers may only begin with a letter, the underscore or a dollar sign.