Java ArrayList.ensureCapacity() Method

public void ensureCapacity(int minCapacity)

The ensureCapacity() method is used to increase the capacity of this ArrayList instance, if necessary, to ensure that it can hold at least the number of elements which is not smaller than the specified size.

Package: java.util

Java Platform: Java SE 8

Syntax:

ensureCapacity(int minCapacity)

Parameters:

Return Value:

This method does not return any value.

Pictorial presentation of ArrayList.ensureCapacity() Method

Example: ArrayList.ensureCapacity Method

import java.util.*;

public class test {
  public static void main(String[] args) {
 
   // ArrayList with Capacity 4
      ArrayList<String> StudentList = new ArrayList<String>(4);
      //Added 4 elements
       StudentList.add("David");
       StudentList.add("Tom");
       StudentList.add("Rohit");
       StudentList.add("Paul");
      
	  //Increase capacity to 10
      StudentList.ensureCapacity(10);

      StudentList.add("Vishal");
      // Print all the elements available in list
      for (String s: StudentList) {
            System.out.println(s);
      }
   }
}

Output:

F:\java>javac test.java
F:\java>java test
David
Tom
Rohit
Paul
Vishal

Java Code Editor:

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