How do I make the method return type generic?
To make the return type of a method generic in Java, you can use a type parameter. A type parameter is a placeholder for a specific type that will be specified when the method is called.
Here's an example of how to define a method with a generic return type:
public class Main {
public static <T> T getValue(T[] array, int index) {
return array[index];
}
}
In this example, the method getValue()
has a type parameter T
, which represents the type of the elements in the array and the return value. The type parameter is specified before the return type T
.
To call this method, you need to specify the type argument for the type parameter. For example:
String[] array = {"apple", "banana", "cherry"};
String value = Main.<String>getValue(array, 1);
This will call the getValue()
method and pass the array array
and the index 1
as arguments. The type argument String
is specified before the method name to indicate that the type parameter T
should be replaced with the String
type.
You can also omit the type argument and let the compiler infer it from the context:
String[] array = {"apple", "banana", "cherry"};
String value = Main.getValue(array, 1);
In this case, the compiler will infer that the type parameter T
should be String
based on the type of the array argument.
Note that the type parameter can be used not only for the return type, but also for the type of the arguments and local variables within the method. For example:
public static <T> void printArray(T[] array) {
for (T element : array) {
System.out.println(element);
}
}