How do I return a generic type in Java?

Can you return a generic type in Java?

(Yes, this is legal code; see Java Generics: Generic type defined as return type only.) The return type will be inferred from the caller.

How do I return a generic list in Java?

1 Answer

  1. private Object actuallyT;
  2. public <T> List<T> magicalListGetter(Class<T> klazz) {
  3. List<T> list = new ArrayList<>();
  4. list.add(klazz.cast(actuallyT));
  5. try {
  6. list.add(klazz.getConstructor().newInstance()); // If default constructor.
  7. } …
  8. return list;

How do you make a return type generic?

The syntax for a generic method includes a list of type parameters, inside angle brackets, which appears before the method’s return type. For static generic methods, the type parameter section must appear before the method’s return type.

How do you declare a generic type in Java?

To update the Box class to use generics, you create a generic type declaration by changing the code “public class Box” to “public class Box<T>”. This introduces the type variable, T, that can be used anywhere inside the class. As you can see, all occurrences of Object are replaced by T.

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How do you change the return type dynamically in Java?

By using a generic for the return type any Java method can dynamically return any object or primitive types. You can name the generic whatever you want, and in this case I called it ‘Any’. Using this code you avoid casting the return type when the method is called.

What is a return method in Java?

A return statement causes the program control to transfer back to the caller of a method. Every method in Java is declared with a return type and it is mandatory for all java methods. A return type may be a primitive type like int, float, double, a reference type or void type(returns nothing).

How do you call a generic method in Java?

To call a generic method, you need to provide types that will be used during the method invocation.

NET object you want to use from Java:

  1. class GenericSample.
  2. {
  3. public void MyGenericMethod<T>(T arg1)
  4. {
  5. return;
  6. }
  7. public K MyGenericMethodWithTwoTypes<T,K>(T arg1)
  8. {

How do I return an integer from a list in Java?

Following are the steps:

  1. Convert the specified primitive array to a sequential stream using Arrays. stream() .
  2. Box each element of the stream to an Integer using IntStream. boxed() .
  3. Use Collectors. toList() to accumulate the input elements into a new list.

What is the correct way of defining generic class?

Which of these is an correct way of defining generic class? Explanation: The type parameter section, delimited by angle brackets (<>), follows the class name. It specifies the type parameters (also called type variables) T1, T2, …, and Tn. 5.

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How does a generic method differ from a generic type?

From the point of view of reflection, the difference between a generic type and an ordinary type is that a generic type has associated with it a set of type parameters (if it is a generic type definition) or type arguments (if it is a constructed type). A generic method differs from an ordinary method in the same way.

How can I return multiple data types in Java?

5 ways to return multiple values from a method in Java

  1. Using a POJO class instance. This is the most commonly used method to return multiple values from a method in Java. …
  2. Using javafx. util. …
  3. Return an array of specific type or an object array. …
  4. Return a Collection.

How do you initialize a generic object in Java?

If you want to initialize Generic object, you need to pass Class<T> object to Java which helps Java to create generic object at runtime by using Java Reflection.

Which of these type parameters is used for a generic class to return?

Which of these type parameters is used for a generic methods to return and accept any type of object? Explanation: T is used for type, A type variable can be any non-primitive type you specify: any class type, any interface type, any array type, or even another type variable. 3.

How do you add two generic values in Java?

But is there any other way to add two generic values.

  1. You have to add the numbers as the same type, so you could do x. intValue() + y. …
  2. you need to use some function of the generic type, just like @Oli said. – JohnnyAW. …
  3. This is kind of a silly (but nevertheless interesting) question. …
  4. Dont agree that this is a duplicate.
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