Java keywords

Java Tutorial - Java Keywords

The full list of keywords in Java

Keywords are words whose meaning is defined by the programming language. Java keywords and reserved words:

abstract class    extends implements null      strictfp     true
assert   const    false   import     package   super        try
boolean  continue final   instanceof private   switch       void
break    default  finally int        protected synchronized volatile
byte     do       float   interface  public    this         while
case     double   for     long       return    throw
catch    else     goto    native     short     throws
char     enum     if      new        static    transient

An identifier is a word that a programmer uses to name variables, methods, classes, or labels. K eywords and reserved words cannot be used as identifiers. rs. ubsequent characters can be letters, dollar signs, underscores, or numbers.

Some examples are:

foobar          // legal
Myclass         // legal
$a              // legal
3_a             // illegal: starts with a digit
!theValue       // illegal: bad 1st  char

Java identifiers are case sensitive. For example, myValue and MyValue are different identifiers.

Use an identifier

Identifiers are used for class names, method names, and variable names. I dentifiers can be capital and lowercase letters, numbers or underscores, and any sequence of dollar sign characters. T he identifier cannot begin with a number. ers: The following code illustrates some examples of valid identifiers:

public class Main {
  public static void main(String[] argv) {
    int ATEST, count, i1, $Atest, this_is_a_test;
  }

}

The following codes show invalid variable names including:

public class Main {
  public static void main(String[] argv){
     int 2count, h-l, a/b, 

  }
}

If you try to compile this code, you will receive the following error message: