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Keywords

Keywords

Keywords are the words that are already defined in language. They are also known as Reserved Words. They are created for specific use ,their working cannot be changed.In java programming language there are 50 reserved words that have different meaning in java.
Initially there are 49 keywords in java till java 1.4 and then "enum" is added with java 1.5 i.e. java 5
keywords are defined in lower case only.
keywords cannot be used as a variable, method, class.


  • List of these 50 java keywords are - 
abstract       continue     for                        new                       switch
assert          default        goto                      package                synchronized
boolean       do                if                          private                  this
break          double         implements         protected              throw
byte             else              import                 public                   throws
case             enum           instanceof           return                   transient
catch           extend         int                        short                     try
char            final             interface             static                     void
class            finally         long                      strictfp                 volatile
const           float            native                   super                    white
  • goto and const are not available for implementation.
  • strictfp is added with java 1.2
  • assert is added with java 1.4
  • enum is added with java 1.5
There are also three Literals that are not keywords but reserved that are predefined in java : true, false, null.

These keywords are defined with different categories i.e. :

Datatypes - boolean, byte, char, double, float, int, short, long.
Modifiers - abstract, const, final, native, static, strictfp, synchronized, transient, volatile,.
Packages - import, package.
Exception Handling - assert, catch, finally, throw, throws, try.
Class & Objects - class, enum, extends, implements, instanceof, interface, new, super, this.
Access Modifiers - private, protected, public.
Control Statement - break, case, continue, default, do, else, for, goto, if, return, switch, while.
Other - void.

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