Size and capacity

int capacity()
Returns the current capacity of this vector.
void ensureCapacity(int minCapacity)
Increases the capacity of this vector, if necessary, to ensure that it can hold at least the number of components specified by the minimum capacity argument.
void setSize(int newSize)
Sets the size of this vector.
int size()
Returns the number of components in this vector.
void trimToSize()
Trims the capacity of this vector to be the vector's current size.

import java.util.Vector;

public class Main{

  public static void main(String args[]) {

    Vector v = new Vector(2000);

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

The output:


2000

import java.util.Vector;

public class Main{

  public static void main(String args[]) {

    Vector v = new Vector(2000);

    System.out.println(v.capacity());
    
    v.add("java2s.com");
    
    v.trimToSize();
    
    System.out.println(v.capacity());
    
  }
}

The output:


2000
1

Set size of Vector


import java.util.Vector;

public class Main {
  public static void main(String[] args) {
    Vector v = new Vector();
    v.add("1");
    v.add("2");
    v.add("3");
    v.add("4");
    v.add("java2s.com");
    v.setSize(3);

    System.out.println(v);

    v.setSize(5);

    System.out.println(v);
  }
}

The output:


[1, 2, 3]
[1, 2, 3, null, null]
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Vector:
  1. Vector class
  2. Create Vector objects
  3. Add elements to this vector
  4. Size and capacity
  5. Remove all elements from a vector
  6. Clone a vector
  7. Does it contain a certain element
  8. Copy elements in vector to an array
  9. Get Enumeration from this vector
  10. Compare two vectors
  11. Get element from vector
  12. Is vector empty
  13. Get element index
  14. Remove element from a vector
  15. Retain elements collection c has
  16. Replace element in a vector
  17. Get a sub list from a list
  18. Convert Vector to Array