Vector In Java

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• The underlying data structure is re-sizable array or growable array.
• Insertion order is preserved.
• Duplicate objects are allowed
• Null insertion is possible.
• Heterogeneous objects are allowed.
• Implements serializable, cloneable & Random Access Interfaces,
• Best suitable if our frequent operation is retrieval & worst choice if our frequent operation is insertion or deletion in the middle.
• Every method in vector is synchronized. Hence vector object is thread safe.

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Constructors of Vector:-

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1. Vector v = new vector();

• Creates an empty object with default initial capacity IO.
• Once vector reaches its max. capacity a new vector object will be created with double capacity

New capacity = 2 * Current capacity

 

2. Vector v = new vector (int initialcapacity);

3 .Vector v = new vector (int initialcapacity, int incrementalcapicity);

4. Vector v = new vector (collection c);

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Vector Specific methods :

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• To add objects

1. Add(object o)
2. Add(int index, object o)
3. AddElement(object obj)

• To remove elements or objects

1. Remove(object o)
2. RemoveElement(object o)
3. Remove(int index)
4. removeElementAt(int index)
5. clear()
6. removeAllElements()

 

• To retrieve elements

1. Get(int index)
2. elementAt(int index)
3. firstElement();
4. LastElement();

 

• Other methods

1. Int size();
2. Int capacity();
3. Enumeration elements();

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Example of Vector:-

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Import java.util.*;

Class Demo

{

public static void main(String[] arg)

{

Vector v = new vector r();

System.out.println(v.capacity());

For (int i = 1; k = 10, i = ++)

{

v.addElement(i);

}

System.out.println(v.capacity());

v.addElement(“A”);

System.out.println(v.capacity());

System.out.println(v);

}

}

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