java list get first element code example

Example 1: find first element of list java

final Object firstElement = list.stream()
  .findFirst()
  .orElse(new Object()) //Give a default value if there are no elements
  
final Object firstElement = list.stream()
  .findFirst()
  .orElseThrow(() -> new Exception()) //Throw an exception if there are no elements

Example 2: java list get first element

list.get(0);

Example 3: java get first element from arraylist

import java.util.ArrayList;
public class FirstandLastElemets{
   public static void main(String[] args){
      ArrayList<String> list = new ArrayList<String>();
      //Instantiating an ArrayList object
      list.add("JavaFX");
      list.add("Java");
      list.add("WebGL");
      list.add("OpenCV");
      list.add("OpenNLP");
      list.add("JOGL");
      list.add("Hadoop");
      list.add("HBase");
      list.add("Flume");
      list.add("Mahout");
      list.add("Impala");
      System.out.println("Contents of the Array List: \n"+list);
      //Removing the sub list
      System.out.println("First element of the array list: "+list.get(0));
      System.out.println("Last element of the array list: "+list.get(list.size()-1));
   }
}

Example 4: java list get first element

set.iterator().next();

Example 5: java list get first element

!list_or_set.isEmpty()