Java type conversions

Java is a strongly-typed language, which means that every variable must be declared with a specific data type. This ensures type safety and prevents unexpected errors during runtime. In Java, type conversions are necessary when we want to assign a value of one data type to a variable of another data type.

Widening and Narrowing Conversions

There are two types of type conversions in Java: Widening and Narrowing conversions.

  • Widening conversion: It is the process of converting a smaller data type to a larger data type. For example, converting an int to a double is a widening conversion.
  • Narrowing conversion: It is the process of converting a larger data type to a smaller data type. For example, converting a double to an int is a narrowing conversion.

Widening Conversion Example

public class WideningConversionExample {
    public static void main(String[] args) {
        int numInt = 10;
        double numDouble = numInt; // Widening conversion from int to double
        System.out.println("Int value: " + numInt);
        System.out.println("Double value: " + numDouble);
    }
}

In the above code snippet, we are converting an int to a double, which is a widening conversion.

Narrowing Conversion Example

public class NarrowingConversionExample {
    public static void main(String[] args) {
        double numDouble = 10.5;
        int numInt = (int) numDouble; // Narrowing conversion from double to int
        System.out.println("Double value: " + numDouble);
        System.out.println("Int value: " + numInt);
    }
}

In the above code snippet, we are converting a double to an int, which is a narrowing conversion. Notice that we need to explicitly cast the double value to an int.

Relationship Diagram

erDiagram
    Widening --|> Conversion
    Narrowing --|> Conversion

The relationship diagram above illustrates the relationship between Widening and Narrowing conversions in Java.

Class Diagram

classDiagram
    class Conversion {
        +int convert()
    }
    class Widening {
        +int toDouble()
    }
    class Narrowing {
        +double toInt()
    }
    Conversion <|-- Widening
    Conversion <|-- Narrowing

The class diagram above shows the classes involved in Widening and Narrowing conversions, along with their methods.

In conclusion, type conversions are essential in Java when dealing with different data types. Understanding the concepts of Widening and Narrowing conversions will help you write efficient and error-free code. Make sure to use the appropriate type conversion based on your requirements to avoid unexpected behavior in your Java programs.