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Identifiers cannot contain special symbols such as!, @, #, %, etc.

                     Identifiers are case-sensitive, so 'name' and 'NAME' are considered different.
                  Examples  of  valid  identifier  names  include  Student1,  total_amount,  userProfile,  GradeA,  and
                  count.
                  Examples  of  invalid  identifier  names  include  the  1st  student,  @total,  123,  grade#,  and
                  student-name.
                  Keywords

                  In Java, keywords are special reserved words that have a predefined meaning and cannot serve
                  as identifiers. The Java language syntax incorporates them for specific operations. Some of the
                  Java keywords are given below:

                                                            Java Keywords
                   abstract            class               final               interface           static

                   assert              const               float               long                switch
                   boolean             continue            for                 new                 this
                   break               default             if                  private             throw
                   byte                do                  implements          protected           throws

                   case                double              import              public              try
                   catch               else                instanceof          return              void
                   char                extends             int                 short               while

                  The keyword const cannot be used in Java.
                  There are three more reserved words in Java: true, false, and null. Technically, they are literal
                  values and not keywords. However, they cannot be used as identifiers, and they have a specific
                  meaning to the Java compiler.

                  Data Types

                  A data type tells you what type of value a variable can store and how much space it will take. In
                  Java, there are two main types of data types: primitive and non-primitive.

                  Primitive Data Types
                  A primitive data type is a basic, built-in data type in Java that holds simple values like numbers,
                  characters, and true or false values.

                  The following table lists the eight fundamental data types that Java offers:

                   Data Type  Size (in bits)              Minimum Value                     Maximum Value
                   byte         8                 –128                               127
                   short        16                –32768                             32767
                   int          32                –2147483648                        2147483647
                   long         64                –9223372036854775808               9223372036854775807
                   char         16                0                                  65535

                   float        32                1.4E –45                           3.4028235E38



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