identifiers in java

1Identifiers are names in java program. Identifiers can be class name, 
2method name or variable name.
3
4  Rules for defining identifiers in java:
51) Identifiers must start with letter, Underscore or dollar($) sign.
62) Identifiers can’t start with numbers .
73) There is no limit on number of characters in identifier but not 
8recommended to have more than 15
9characters
104) Java identifiers are case sensitive.
115) First letter can be alphabet ,or underscore and dollar sign. 
12From second letter we can have numbers
136) We should’nt use reserve words for identifiers in java.