Java · Theory

Difference Between ArrayList and LinkedList in Java

Theory

197/270

Difference Between ArrayList and LinkedList in Java

ArrayList is a resizable array: fast get(i), slower insert in the middle. LinkedList is a node chain: faster insert/delete at ends, slower random get(i).

Almost every fresher program should use ArrayList. Use LinkedList only when you truly insert/delete a lot at the ends.

Both implement List. Both allow duplicates and keep order. Pick by operation, not by name.

Let's take this on the board with one tiny Main class — no extra files. Difference Between ArrayList and LinkedList in Java — output: 2 then Asha. add Asha, add Ravi. size is 2. get(0) is Asha. get(2) would throw IndexOutOfBoundsException. Start from main, go line by line, and stop at each print. That output is the proof for Difference Between ArrayList and LinkedList.

Diagram

ArrayList names
    add("Asha")  add("Ravi")
         │
         ▼
    [0]=Asha  [1]=Ravi   size=2

Exam tip

Default ArrayList. LinkedList only if lots of insert/delete at ends. Say why get(i) differs.

Example

import java.util.ArrayList;

// ArrayList demo
public class Main {
  public static void main(String[] args) {
    ArrayList<String> names = new ArrayList<>();
    names.add("Asha");
    names.add("Ravi");
    System.out.println(names.size());
    System.out.println(names.get(0));
  }
}

Difference Between ArrayList and LinkedList in Java — output: 2 then Asha. add Asha, add Ravi. size is 2. get(0) is Asha. get(2) would throw IndexOutOfBoundsException.

Short notes

DefArrayList = resizable array. LinkedList = node chain.
DiffArrayList fast get(i). LinkedList fast end insert/delete.
UseDefault ArrayList. LinkedList only for end-heavy edits.
RememberBoth are List — order + duplicates OK.

Java · Theory

Difference Between ArrayList and LinkedList in Java

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Theory

197/270

Difference Between ArrayList and LinkedList in Java

ArrayList is a resizable array: fast get(i), slower insert in the middle. LinkedList is a node chain: faster insert/delete at ends, slower random get(i).

Almost every fresher program should use ArrayList. Use LinkedList only when you truly insert/delete a lot at the ends.

Both implement List. Both allow duplicates and keep order. Pick by operation, not by name.

Diagram

ArrayList names
    add("Asha")  add("Ravi")
         │
         ▼
    [0]=Asha  [1]=Ravi   size=2

Exam tip

Default ArrayList. LinkedList only if lots of insert/delete at ends. Say why get(i) differs.

Example

import java.util.ArrayList;

// ArrayList demo
public class Main {
  public static void main(String[] args) {
    ArrayList<String> names = new ArrayList<>();
    names.add("Asha");
    names.add("Ravi");
    System.out.println(names.size());
    System.out.println(names.get(0));
  }
}

Difference Between ArrayList and LinkedList in Java — output: 2 then Asha. add Asha, add Ravi. size is 2. get(0) is Asha. get(2) would throw IndexOutOfBoundsException.

Short notes

DefArrayList = resizable array. LinkedList = node chain.
DiffArrayList fast get(i). LinkedList fast end insert/delete.
UseDefault ArrayList. LinkedList only for end-heavy edits.
RememberBoth are List — order + duplicates OK.

Difference Between ArrayList and LinkedList in Java

Example

Short notes

Questions

Difference Between ArrayList and LinkedList in Java

Example

Short notes

Questions