The toArray() method of CopyOnWriteArrayList is used to return an array containing all the elements in CopyOnWriteArrayList in the correct order.
Syntax:
public Object[] toArray() or public <T> T[] toArray(T[] a)
Parameters: This method either accepts no parameters or it takes an array T[] a as parameter which is the array into which the elements of the list are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.
Return Value: The function returns an array containing all the elements in this list.
Exception: The first overload of this method throws no exceptions. However, the second overload throws following exceptions:
- ArrayStoreException: if the runtime type of the specified array is not a supertype of the runtime type of every element in this list.
- NullPointerException if the specified array is null
Below programs illustrate the CopyOnWriteArrayList.toArray() method:
Program 1:
// Java Program to illustrate the // CopyOnWriteArrayList toArray() method in Java import java.util.concurrent.CopyOnWriteArrayList; import java.util.*; public class GFG { public static void main(String[] args) { // create object of CopyOnWriteArrayList CopyOnWriteArrayList<Integer> ArrLis = new CopyOnWriteArrayList<Integer>(); // Add elements ArrLis.add( 32 ); ArrLis.add( 67 ); ArrLis.add( 98 ); ArrLis.add( 100 ); // print CopyOnWriteArrayList System.out.println( "CopyOnWriteArrayList: " + ArrLis); // Get the array of the elements // of the CopyOnWriteArrayList // using toArray() method Object[] arr = ArrLis.toArray(); System.out.println( "Elements of CopyOnWriteArrayList" + " as Array: " + Arrays.toString(arr)); } } |
CopyOnWriteArrayList: [32, 67, 98, 100] Elements of CopyOnWriteArrayList as Array: [32, 67, 98, 100]
Program 2:
// Java Program to illustrate the // CopyOnWriteArrayList toArray(T[]) method in Java import java.util.concurrent.CopyOnWriteArrayList; import java.util.*; public class GFG { public static void main(String[] args) { // create object of CopyOnWriteArrayList CopyOnWriteArrayList<Integer> ArrLis = new CopyOnWriteArrayList<Integer>(); // Add elements ArrLis.add( 32 ); ArrLis.add( 67 ); ArrLis.add( 98 ); ArrLis.add( 100 ); // print CopyOnWriteArrayList System.out.println( "CopyOnWriteArrayList: " + ArrLis); // Get the array of the elements // of the CopyOnWriteArrayList // using toArray(T[]) method Integer arr[] = new Integer[ArrLis.size()]; arr = ArrLis.toArray(arr); System.out.println( "Elements of CopyOnWriteArrayList" + " as Array: " + Arrays.toString(arr)); } } |
CopyOnWriteArrayList: [32, 67, 98, 100] Elements of CopyOnWriteArrayList as Array: [32, 67, 98, 100]
Reference: CopyOnWriteArrayList.toArray() doc, CopyOnWriteArrayList.toArray(T[]) doc
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