If you are wondering what <E>, <K, V>, <N> and so on are called in Java Generics? Well, they are known as "Type Parameters".
![Java Genetics E - K - V - T - U - V Type Parameters Java Genetics E - K - V - T - U - V Type Parameters](https://code2care.org/java/what-are-e-k-n-s-t-u-v-in-java-genetics/images/Java Genetics E - K - V - T - U - V Type Parameters.jpg)
Type Parameters are placeholders for data types that are defined when creating generic classes, interfaces, or methods. They are specified inside angle brackets (<>) when defining a generic class, interface, or method.
Examples:
Genetic Interface with Type Parameter E:
interface Payment<E> {
void process(E payment);
}
Genetic Method with Type Parameter E:
public <E> void printElement(E element) {
System.out.println(element);
}
Genetic Class with Type Parameter E:
class Container<E> {
private E item;
public Container(E item) {
this.item = item;
}
public E getItem() {
return item;
}
}
Naming Conventions of Type Parameters:
The Type Parameters are represented by single uppercase letters e.g., E, T, K, V.
Naming Convention | Type Parameter | Usage | Example |
---|---|---|---|
E | Element | Used extensively by the Java Collections Framework | List<E> |
K | Key | Typically used in key-value pairs or maps | Map<K, V> |
N | Number | Often used for numeric types | List<Number> |
T | Type | A general-purpose type parameter | Box<T> |
V | Value | Commonly used in key-value pairs or maps | Map<String, V> |
S , U , V , etc. | 2nd, 3rd, 4th types | Used for additional type parameters | Pair<S, T> , Triple<U, V, W> |
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