Introduction to Java Generics

Java generics are a feature of the Java language that allows type checking at compile time, thereby enhancing the type safety of the code. Generics can be used in the definition of classes, interfaces and methods, allowing These definitions have wider applicability and reusability, and using generics minimizes the risk of type conversion errors and makes code more concise and easier to read. Generics can also reduce redundancy in code and avoid unnecessary casts.

Java generics are a feature of the Java language that allows type checking at compile time, thereby enhancing the type safety of the code. Generics can be used in the definition of classes, interfaces, and methods to make these definitions more widely applicable and reusable.

Using generics minimizes the risk of type conversion errors and makes code more concise and easier to read. Generics can also reduce redundancy in code and avoid unnecessary casts.

The core concept of Java generics is type parameter (Type Parameter), which is a placeholder type used to represent an unknown type. When using generics, we need to specify type parameters so that the compiler knows what type to use for type checking and type conversion.

For example, define a generic class:

public class MyList<T> {
    private T[] array;

    public MyList(T[] array) {
        this.array = array;
    }

    public T get(int index) {
        return array[index];
    }
}

In the above example, we use the type parameter T, indicating that this class can accept elements of any type. When using this class, we need to specify the specific type of the type parameter, for example:

MyList<String> list = new MyList<>(new String[]{"a", "b", "c"});
String s = list.get(0);

When instantiating the MyList object, we specify the type parameter as String, so this object can only store elements of string type. . When calling the get method, the type of the return value is automatically converted to the String type, thus avoiding the risk of type conversion errors.

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