Value Types Reference Issue - Derrick

[Pitsco]

Value Types (Primitive Types)

General Information

• Primitive types in Java consist of boolean and numeric types: char, byte, short, int, long, float, and double.
• Unlike reference types, the number of primitive types is limited and predefined in the language.
• Memory location for primitive types directly stores the actual data held by the variable, not a reference to it.

Differences

1. Number and Definition:

   • Reference Types: Unlimited number, defined by the user.
   • Primitive Types: Limited and predefined in the language.

2. Memory Location:

   • Reference Types: Stores a reference to the data in memory.
   • Primitive Types: Stores the actual data held by the variable.

3. Assignment (Note the Difference!):

   • Reference Types: When assigned to another reference type, both references point to the same object in memory.
   • Primitive Types: When assigned to another variable of the same type, a copy of the data is made.

4. Method Parameter Passing:

   • Reference Types: When an object is passed into a method, the method can change the contents of the object, but not the address/reference of the object.
   • Primitive Types: When a primitive is passed into a method, only a copy of the primitive is passed. The called method does not have access to the original primitive value and can only change the copied value.

public class PrimitiveTypesExample {
    public static void main(String[] args) {
        // Declaration and initialization of primitive variables
        boolean isJavaFun = true;
        char grade = 'A';
        byte byteValue = 127; // byte range: -128 to 127
        short shortValue = 32000; // short range: -32,768 to 32,767
        int intValue = 42;
        long longValue = 123456789L; // The 'L' indicates a long literal
        float floatValue = 3.14f; // The 'f' indicates a float literal
        double doubleValue = 2.71828;

        // Displaying values
        System.out.println("Is Java fun? " + isJavaFun);
        System.out.println("Grade: " + grade);
        System.out.println("Byte Value: " + byteValue);
        System.out.println("Short Value: " + shortValue);
        System.out.println("Int Value: " + intValue);
        System.out.println("Long Value: " + longValue);
        System.out.println("Float Value: " + floatValue);
        System.out.println("Double Value: " + doubleValue);
    }
}