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When you declare a variable, you explicitly set the variable's name and data type. The Java programming language has two categories of data types: primitive and reference. A variable of primitive type contains a value. This table shows all of the primitive data types along with their sizes and formats:
Keyword Description Size/Format (integers) byteByte-length integer 8-bit two's complement shortShort integer 16-bit two's complement intInteger 32-bit two's complement longLong integer 64-bit two's complement (real numbers) floatSingle-precision floating point 32-bit IEEE 754 doubleDouble-precision floating point 64-bit IEEE 754 (other types) charA single character 16-bit Unicode character booleanA boolean value ( trueorfalse)true or false The location of a variable declaration implicitly sets the variable's scope, which determines what section of code may refer to the variable by its simple name. There are four categories of scope: member variable scope, local variable scope, parameter scope, and exception-handler parameter scope.
You can provide an initial value for a variable within its declaration by using the assignment operator (=).
You can declare a variable as final. The value of a final variable cannot change after it's been initialized.
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