Generics
Generics in collections
- Generics are mainly used in collections.
- Generics are mainly used to store specific types of objects.
- Generics are always defined inside the angular braces(<>).
Advantages:
- It can hold only a single type of object, it doesn't allow it to store other objects.
- There is no need to typecast the objects.
- Compile time checking: It is checked at compile time so the problem will not occur at runtime.
Example:
package quipoin;
import java.util.ArrayList;
public class DemoGeneric {
public static void main(String[] args) {
ArrayList<String> list = new ArrayList<>();
list.add("Java");
list.add("Python");
list.add("Web_Technology");
// list.add(20); compilation error because of int type.
System.out.println("Storing string type objects using generics!!");
for (String elements : list) {
System.out.println(elements);
}
}
}
Output:
Storing string-type objects using generics!!
Java
Python
Web_Technology
- In the above example, we are storing specific types of objects i.e. String type, if we are trying to store other type objects compiler throws an error.