How to call an arraylist from another class in java?

You should make your variable arrayList part of the class as a field: public class Friends { List arrayList; public Friends(float x, float y) { arrayList = new ArrayList(); MyObject[] friendList = new MyObject[20]; } public void add() { for (int i = 0; i < 20; i++) { //arrayList.

How do you call an array from another class in Java?

  1. By Creating an Object of other class and use that object to invoke the array from your class.
  2. For Example –
  3. You have two classes A and B.
  4. Now, You have something like this in A class –
  5. Now create another class B and create the object of class A in that class –

How do you pass a list to another class in Java?

Create a list using an java. util. ArrayList in the main() of the Sample class. Pass the same ArrayList to constructor of both Read and Write class constructor and initialize the list fields of both class.

How do you call a list method in Java?

  1. Syntax :
  2. Parameter : This method accepts a single parameter index of type integer which represents the index of the element in this list which is to be returned.
  3. Return Value: It returns the element at the specified index in the given list.

What is the capacity of ArrayList in Java?

Whenever an instance of ArrayList in Java is created then by default the capacity of Arraylist is 10. Since ArrayList is a growable array, it automatically resizes itself whenever a number of elements in ArrayList grow beyond a threshold. However, ensureCapacity() method of java.

How do you access an array from another method?

  1. Access the array through an instance variable of array type, or.
  2. Pass the array to methods as a parameter.

How do you create an array of another class?

Creating an Array Of Objects In Java – An Array of Objects is created using the Object class, and we know Object class is the root class of all Classes. We use the Class_Name followed by a square bracket [] then object reference name to create an Array of Objects.

What is array in Java?

An array in Java is a set of variables referenced by using a single variable name combined with an index number. Each item of an array is an element. All the elements in an array must be of the same type. … An int array can contain int values, for example, and a String array can contain strings.

How can I get a list from another class?

To access the list from another class you need to have a reference to an object of type Foo . Assuming that you have such a reference and it is called foo then you can write foo. MyList to access the list. You might want to be careful about exposing Lists directly.

How do you pass objects in ArrayList?

ArrayList cannot hold primitive data types such as int, double, char, and long. With the introduction to wrapped class in java that was created to hold primitive data values. Objects of these types hold one value of their corresponding primitive type(int, double, short, byte).

How do you clone an ArrayList?

  1. Create a cloneable class, which has the clone method overridden.
  2. Create a list of the class objects from an array using the asList method.
  3. Create an empty list.

What is get () in Java?

get() is an inbuilt method in Java and is used to return the element at a given index from the specified Array. Syntax Array.get(Object []array, int index) Parameters : This method accepts two mandatory parameters: array: The object array whose index is to be returned.

How do you access values in an ArrayList?

The get() method of the ArrayList class accepts an integer representing the index value and, returns the element of the current ArrayList object at the specified index. Therefore, if you pass 0 to this method you can get the first element of the current ArrayList and, if you pass list.

How do you declare a list?

  1. Using List.add() method. Since list is an interface, one can’t directly instantiate it.
  2. Using Arrays. asList()
  3. Using Collections class methods. There are various methods in Collections class that can be used to instantiate a list.
  4. Using Java 8 Stream.
  5. Using Java 9 List.

Does ArrayList have size?

The size of an ArrayList can be obtained by using the java. … size() method as it returns the number of elements in the ArrayList i.e. the size.