A Vector in Java functions similarly to a dynamic array, allowing for the adjustment of its size. In contrast to a regular array, a Vector can accommodate any number of elements without a fixed limit. This data structure has been integrated into the Java Collection framework from Java version 1.2. Situated within the java.util package, it adheres to the List interface, granting access to all List interface functionalities.
It is advisable to utilize the Vector class specifically for thread-safe implementations. In scenarios where thread safety is not a requirement, opting for the ArrayList is recommended as it offers better performance in such instances.
The iterators provided by the Vector class are designed to be fail-fast. This means that if there are concurrent modifications, the iterator will fail and throw a ConcurrentModificationException.
It resembles the ArrayList in functionality, but there are two key distinctions:
- Vector in Java is synchronized.
- Java Vector includes numerous legacy methods that are not part of the collections framework.
Java Vector class Declaration
Example
public class Vector<E>
extends Object<E>
implements List<E>, Cloneable, Serializable
Java Vector Constructors
The Vector class provides support for four different types of constructors, as listed:
| SN | Constructor | Description |
|---|---|---|
| 1) | vector() | It constructs an empty vector with the default size as 10. |
| 2) | vector(int initialCapacity) | It constructs an empty vector with the specified initial capacity and with its capacity increment equal to zero. |
| 3) | vector(int initialCapacity, int capacityIncrement) | It constructs an empty vector with the specified initial capacity and capacity increment. |
| 4) | Vector( Collection<? extends E> c) | It constructs a vector that contains the elements of a collection c. |
Java Vector Methods
Below are the Vector class methods that are available for use:
| SN | Method | Description |
|---|---|---|
| 1) | add() | It is used to append the specified element in the given vector. |
| 2) | addAll() | It is used to append all of the elements in the specified collection to the end of this Vector. |
| 3) | addElement() | It is used to append the specified component to the end of this vector. It increases the vector size by one. |
| 4) | capacity() | It is used to get the current capacity of this vector. |
| 5) | clear() | It is used to delete all of the elements from this vector. |
| 6) | clone() | It returns a clone of this vector. |
| 7) | contains() | It returns true if the vector contains the specified element. |
| 8) | containsAll() | It returns true if the vector contains all of the elements in the specified collection. |
| 9) | copyInto() | It is used to copy the components of the vector into the specified array. |
| 10) | elementAt() | It is used to get the component at the specified index. |
| 11) | elements() | It returns an enumeration of the components of a vector. |
| 12) | ensureCapacity() | It is used to increase the capacity of the vector which is in use, if necessary. It ensures that the vector can hold at least the number of components specified by the minimum capacity argument. |
| 13) | equals() | It is used to compare the specified object with the vector for equality. |
| 14) | firstElement() | It is used to get the first component of the vector. |
| 15) | forEach() | It is used to perform the given action for each element of the Iterable until all elements have been processed or the action throws an exception. |
| 16) | get() | It is used to get an element at the specified position in the vector. |
| 17) | hashCode() | It is used to get the hash code value of a vector. |
| 18) | indexOf() | It is used to get the index of the first occurrence of the specified element in the vector. It returns -1 if the vector does not contain the element. |
| 19) | insertElementAt() | It is used to insert the specified object as a component in the given vector at the specified index. |
| 20) | isEmpty() | It is used to check if this vector has no components. |
| 21) | iterator() | It is used to get an iterator over the elements in the list in proper sequence. |
| 22) | lastElement() | It is used to get the last component of the vector. |
| 23) | lastIndexOf() | It is used to get the index of the last occurrence of the specified element in the vector. It returns -1 if the vector does not contain the element. |
| 24) | listIterator() | It is used to get a list iterator over the elements in the list in proper sequence. |
| 25) | remove() | It is used to remove the specified element from the vector. If the vector does not contain the element, it is unchanged. |
| 26) | removeAll() | It is used to delete all the elements from the vector that are present in the specified collection. |
| 27) | removeAllElements() | It is used to remove all elements from the vector and set the size of the vector to zero. |
| 28) | removeElement() | It is used to remove the first (lowest-indexed) occurrence of the argument from the vector. |
| 29) | removeElementAt() | It is used to delete the component at the specified index. |
| 30) | removeIf() | It is used to remove all of the elements of the collection that satisfy the given predicate. |
| 31) | removeRange() | It is used to delete all of the elements from the vector whose index is between fromIndex, inclusive and toIndex, exclusive. |
| 32) | replaceAll() | It is used to replace each element of the list with the result of applying the operator to that element. |
| 33) | retainAll() | It is used to retain only that element in the vector which is contained in the specified collection. |
| 34) | set() | It is used to replace the element at the specified position in the vector with the specified element. |
| 35) | setElementAt() | It is used to set the component at the specified index of the vector to the specified object. |
| 36) | setSize() | It is used to set the size of the given vector. |
| 37) | size() | It is used to get the number of components in the given vector. |
| 38) | sort() | It is used to sort the list according to the order induced by the specified Comparator. |
| 39) | spliterator() | It is used to create a late-binding and fail-fast Spliterator over the elements in the list. |
| 40) | subList() | It is used to get a view of the portion of the list between fromIndex, inclusive, and toIndex, exclusive. |
| 41) | toArray() | It is used to get an array containing all of the elements in this vector in correct order. |
| 42) | toString() | It is used to get a string representation of the vector. |
| 43) | trimToSize() | It is used to trim the capacity of the vector to the vector's current size. |
Java Vector Example
Example
Example
import java.util.*;
public class Main {
public static void main(String args[]) {
//Create a vector
Vector<String> vec = new Vector<String>();
//Adding elements using add() method of List
vec.add("Tiger");
vec.add("Lion");
vec.add("Dog");
vec.add("Elephant");
//Adding elements using addElement() method of Vector
vec.addElement("Rat");
vec.addElement("Cat");
vec.addElement("Deer");
System.out.println("Elements are: "+vec);
}
}
Output:
Output
Elements are: [Tiger, Lion, Dog, Elephant, Rat, Cat, Deer]
Java Vector Example 2
Example
Example
import java.util.*;
public class Main {
public static void main(String args[]) {
//Create an empty vector with initial capacity 4
Vector<String> vec = new Vector<String>(4);
//Adding elements to a vector
vec.add("Tiger");
vec.add("Lion");
vec.add("Dog");
vec.add("Elephant");
//Check size and capacity
System.out.println("Size is: "+vec.size());
System.out.println("Default capacity is: "+vec.capacity());
//Display Vector elements
System.out.println("Vector element is: "+vec);
vec.addElement("Rat");
vec.addElement("Cat");
vec.addElement("Deer");
//Again check size and capacity after two insertions
System.out.println("Size after addition: "+vec.size());
System.out.println("Capacity after addition is: "+vec.capacity());
//Display Vector elements again
System.out.println("Elements are: "+vec);
//Checking if Tiger is present or not in this vector
if(vec.contains("Tiger"))
{
System.out.println("Tiger is present at the index " +vec.indexOf("Tiger"));
}
else
{
System.out.println("Tiger is not present in the list.");
}
//Get the first element
System.out.println("The first animal of the vector is = "+vec.firstElement());
//Get the last element
System.out.println("The last animal of the vector is = "+vec.lastElement());
}
}
Output:
Output
Size is: 4
Default capacity is: 4
Vector element is: [Tiger, Lion, Dog, Elephant]
Size after addition: 7
Capacity after addition is: 8
Elements are: [Tiger, Lion, Dog, Elephant, Rat, Cat, Deer]
Tiger is present at the index 0
The first animal of the vector is = Tiger
The last animal of the vector is = Deer
Java Vector Example 3
Example
Example
import java.util.*;
public class Main {
public static void main(String args[]) {
//Create an empty Vector
Vector<Integer> in = new Vector<>();
//Add elements in the vector
in.add(100);
in.add(200);
in.add(300);
in.add(200);
in.add(400);
in.add(500);
in.add(600);
in.add(700);
//Display the vector elements
System.out.println("Values in vector: " +in);
//use remove() method to delete the first occurence of an element
System.out.println("Remove first occourence of element 200: "+in.remove((Integer)200));
//Display the vector elements afre remove() method
System.out.println("Values in vector: " +in);
//Remove the element at index 4
System.out.println("Remove element at index 4: " +in.remove(4));
System.out.println("New Value list in vector: " +in);
//Remove an element
in.removeElementAt(5);
//Checking vector and displays the element
System.out.println("Vector element after removal: " +in);
//Get the hashcode for this vector
System.out.println("Hash code of this vector = "+in.hashCode());
//Get the element at specified index
System.out.println("Element at index 1 is = "+in.get(1));
}
}
Output:
Output
Values in vector: [100, 200, 300, 200, 400, 500, 600, 700]
Remove first occourence of element 200: true
Values in vector: [100, 300, 200, 400, 500, 600, 700]
Remove element at index 4: 500
New Value list in vector: [100, 300, 200, 400, 600, 700]
Vector element after removal: [100, 300, 200, 400, 600]
Hash code of this vector = 130123751
Element at index 1 is = 300