Explanation of Generic Classes in Java

Explanation of Generic Classes in Java

Hello everyone, in this article we are going to talk about Generic classes in Java programming language with code examples for better understanding.

Lets get started.

Generic classes are the one of the efficient way to create structures to work with different types of data with safe development. It is an efficient way to create flexible and reusable classes and interfaces in Java.

Understanding Generic Classes

Generic classes allow us to create interfaces, classes and some other structures which is able to take objects as a parameter to work with different types of object with same implementation with keeping type safe implementation. Generic classes are improving the reusable code implementation with more clean and maintainable way. Generally we can see the generic classes usages with Collections (List, Vector, Set, Map...) in Java.

Now lets dive in how to implement a Generic Class in Java.

To create a generic class, We declare the class with angled brackets ( < ... >) with parameter to represent the class to work with. The type of the parameter can be any valid identifier. Below you can see how to declare a Generic Class in Java

class GenericClassExample {
    public static class TheGeneric<T> {
        private T value;
        public TheGeneric(T value) {
            this.value = value;
        public T getValue() {
            return value;
        public void setValue(T value) {
            this.value = value;
    public static void main(String[] args) {
        TheGeneric<Integer> generic1 = new TheGeneric<>(12345);
        TheGeneric<String> generic2 = new TheGeneric<>("Thecodeprogram");
        TheGeneric<Boolean> generic3 = new TheGeneric<>(false);
Program Output will be like below


As you can see above we have defined our class with generic identifier in angled brackets after the class definition. Inside the class we added some functions to handle the generic object which is represented by the generic identifier instance. In the main function we have just initialised the Generic Class and used same method for all of data types to get the value which is wrapping by the Generic class.

Now, we know how to create a generic class, Now lets create some generic methods.

We can create generic methods to work with different data types with same code. Below code block you will see definitions of creating Generic functions which can take different types of object. We used these generic methods to print the different types of data.

class GenericClassExample {
    public static <T> void printIndividual(T data){
        System.out.print(data + " ");
    public static <T> void printGenericArray(T[] array) {
        for (T el : array) {
    public static void main(String[] args) {
        Integer[] numbers = { 10, 20, 30, 40, 50 };
        String[] strings = { "the", "code", "program" };


As you can above code block we have declared two methods which are working with Generic data types and we have called them with the different types of data to print the datas.

Advantages of Generic classes:
  • Clean Code: With generics we can reduce the object casting for some types of data and we can reduce the complexity.
  • Reusable Code: Generic classes allows us to declare classes and methods to work with different types of data with same code.
  • Improved Performance: Generic classes are allowing to improve the performance since avoiding the use the casting will prevent the runtime checks.
  • Type Safety: With generic classes type safety is checking during the compiling time, so it will avoid the data types issues before compilation of program.


Generics are efficient feature of Java that allows us to create more flexible and clean classes to work with different data types. Generics are allowing us to create more reusable and clean codes with type safety when working with different types of data. Usage of the Generics will improve the performance of the program and the maintainability of the codebase.

That is all

Burak Hamdi TUFAN


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