Java Primitive Types (8 + 1)

Primitive types are fundamental data types in Java. In Java, primitive types refer to types that store actual data values, such as integers, floating-point numbers, characters, and boolean literals. They offer fast access and occupy less memory.

• Data type: The type of data I need.

Booleans

• The boolean data type represents true and false.
• Primarily used in conditional testing.

boolean isJavaFun = true;
boolean isFoodTasty = false;
System.out.println(isJavaFun);     // Outputs true
System.out.println(isFoodTasty);   // Outputs false

Characters

• Used to store single characters like "A", "B".

char myGrade = 'B';
System.out.println(myGrade);  //B

Numbers

1. Integer types - ① byte, ② short, ③ int, ④ long

   ① byte

   • Can hold integers in the range of -128 to 127.
   • Can save memory compared to int or other integer types in certain situations.

   byte myNum = 120;
   System.out.println(myNum); //120
   
   

   ② short

   • Can hold integers in the range of -32768 to 32767.

   short myNum = 5000;
   System.out.println(myNum); //5000
   
   

   ③ int

   • Can hold integers in the range of -2147483648 to 2147483647.
   • The preferred type when declaring variables.

   int myNum = 120000;
   System.out.println(myNum); //120000
   
   

   ④ long

   • Can hold integers in the range of -9223372036854775808 to 9223372036854775807.
   • Used when int is not sufficient.
   • Should end with "L".

   long myNum = 12000000000L;
   System.out.println(myNum); //12000000000
   
   

2. Floating-point types - ① float, ② double

   ① float

   • Can hold real numbers in the range of approximately 3.4e−038 to 3.4e+038.

   float myNum = 5.75f;
   System.out.println(myNum); //5.75
   
   

   ② double

   • Can hold real numbers in the range of approximately 1.7e−308 to 1.7e+308.
   • Should end with "d".

   double myNum = 19.99d;
   System.out.println(myNum); //19.99
   
   

   ③ Scientific Notation

   • Floating-point types can represent numbers in scientific notation using "e".

   float f1 = 35e3f;
   double d1 = 12E4d;
   System.out.println(f1); //35000.0
   System.out.println(d1); //120000.0
   
   

   💡 A float variable can handle 6-7 digits, while a double variable can handle up to 15 digits. Therefore, double is considered safer.

String

• Used to store text.
• Text must be enclosed in double quotes.

String greeting = "Hello World";
System.out.println(greeting);  //Hello World

💡 The String type is commonly used and is often referred to as the 9th type. However, it is not a primitive type because it is a reference type.