JAVA EXAMPLE PROGRAMS

JAVA EXAMPLE PROGRAMS

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Program: How to read first element from LinkedList?


Description:

Below example shows how to read first element from LinkedList. LinkedList provides few methods to read first element, those methods are:

element(): Retrieves, but does not remove, the head (first element) of this list.
getFirst(): Returns the first element in this list.
peek(): Retrieves, but does not remove, the head (first element) of this list.
peekFirst(): Retrieves, but does not remove, the first element of this list, or returns null if this list is empty.


Code:
package com.java2novice.linkedlist;

import java.util.LinkedList;

public class MyFirstElement {

	public static void main(String a[]){
		
		LinkedList<String> arrl = new LinkedList<String>();
		arrl.add("First");
		arrl.add("Second");
		arrl.add("Third");
		arrl.add("Random");
		System.out.println("First Element: "+arrl.element());
		System.out.println("First Element: "+arrl.getFirst());
		System.out.println("First Element: "+arrl.peek());
		System.out.println("First Element: "+arrl.peekFirst());
	}
}

Output:
First Element: First
First Element: First
First Element: First
First Element: First
<< Previous Program | Next Program >>

List Of All LinkedList Sample Programs:

  1. Basic LinkedList Operations.
  2. How to read all elements in LinkedList by using iterator?
  3. How to copy or clone a LinkedList?
  4. How to add all elements of a list to LinkedList?
  5. How to delete all elements from my LinkedList?
  6. How to find does LinkedList contains all list elements or not?
  7. How to copy LinkedList to array?
  8. How to get sub list from LinkedList?
  9. How to sort LinkedList using Comparator?
  10. How to reverse LinkedList content?
  11. How to shuffle elements in LinkedList?
  12. How to swap two elements in a LinkedList?
  13. How to convert list to csv string format?
  14. How to add element at first position in LinkedList?
  15. How to add element at last position in LinkedList?
  16. How to read first element from LinkedList?
  17. How to read last element from LinkedList?
  18. How to iterate through LinkedList in reverse order?
  19. LinkedList push(), pop() operations examples.
  20. How to remove elements from LinkedList?
Knowledge Centre
When to use LinkedList or ArrayList?
Accessing elements are faster with ArrayList, because it is index based. But accessing is difficult with LinkedList. It is slow access. This is to access any element, you need to navigate through the elements one by one. But insertion and deletion is much faster with LinkedList, because if you know the node, just change the pointers before or after nodes. Insertion and deletion is slow with ArrayList, this is because, during these operations ArrayList need to adjust the indexes according to deletion or insetion if you are performing on middle indexes. Means, an ArrayList having 10 elements, if you are inserting at index 5, then you need to shift the indexes above 5 to one more.
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About Author

I'm Nataraja Gootooru, programmer by profession and passionate about technologies. All examples given here are as simple as possible to help beginners. The source code is compiled and tested in my dev environment.

If you come across any mistakes or bugs, please email me to [email protected].

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Reference: Java™ Platform Standard Ed. 7 - API Specification | Java™ Platform Standard Ed. 8 - API Specification | Java is registered trademark of Oracle.
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