Top 10 uses of Java Keywords

Keyword:

• Keywords are predefined identifiers available directly throughout the JVM.
• They have a special meaning inside java source code and outside of comments and strings.
• For Example : public, static, void

Rules:

• Keywords can not be used as user defined identifier by the programmer either for variable or method or class names, because keywords are reserved for their intended use.
• All characters in keyword must be used in lower case.

Need of keywords:

• Basically keywords are used to communicate with compiler and JVM about the operation we perform in java application.
• In java we perform 10 different operations using keywords
• They are:

1. Creating Java file
2. Storing data temporary
3. Creating memory locations
4. Controlling calculations
5. Setting accessibility permissions
6. Modifying default properties
7. Object representation
8. Establishing relations between classes
9. Grouping classes
10. Handling user mistakes

• In java we have 50 keywords to perform all above 10 operations
• Among them 47 introduced in java 1.0
• In Java 1.2 new keyword "strictfp" was added.
• In Java 1.4 new keyword "assert" was added
• In Java 5 new keyword "enum" was added

• Among 50 keywords 2 keywords are reserved words they can not be used in java program, because they defined but they are not implemented , those two are,

1. goto
2. const

     

1.Java Files

1.class
2.interface
3.enum

2.Data Types

4.byte
5.short
6.int
7.long
8.float
9.double
10.char
11.boolean
12.void

3.Memory Location

13.static
14.new

4.Control Statements

1.conditional

15.if

16.else

17.switch

18.case

19.default

2.loop

20.while

21.do

22.for

3.transfer

23.break

24.continue

25.return

5.Accessibility Modifiers

26.private

27.protected

28.public

6.Modifiers

28.static // used as modifier and class level memory allocation

29.final

30.abstract

31.native

32.transient

33.volatile

34.synchronized

35.strictfp

7.Object Representation

36.this

37.super

38.instanceof

8.Inheritance Relationship

39.extends

40.implements

9.Package

41.package

42.import

10.Exception Handling

43.try

44.catch

45.finally

46.throw

47.throws

48.assert

11.Unused keywords

49.const

50.goto

Default literals:

1.referenced literal

  ->null

2.boolean literals

->true

->false