An element can be added in any position in the list.
By default in list the position of new element is last if you not specify its position.
The same element is allowed in the list multiple times.
Note : At end git link is there for reference
Defining List in Java
By using List.of() method list becomes immutable, so we cannot add any new element in it. To make it mutable we use arrayList
package listInterface;
import java.util.List;
public class ListClass {
public static void main(String[] args) {
// Defining the list
List<String> alphabets = List.of("A", "B", "C", "D");
System.out.println(alphabets);
}
}
Array List in Java
Presents since 1.2 version of java
Traversing is fast as it works on indexes.
Adding and deleting elements is time-consuming.
Suitable when there is less insertion and deletion and we want to access elements using their position.
Most method of the vector is not Synchronized i.e. it is not thread-safe.
If you don’t worry about thread safety, then go with vectors.
Linked List in Java
Traversing is time-consuming.
Adding and Deleting any element is fast.
Going to any specific position is time-consuming.
Suitable when there is more addition and deletion of elements and less accessing of elements.
Vector List in Java
Presents since 1st version of Java.
Most method of the vector is Synchronized i.e it is thread-safe.
Almost time-constant access.
If you worry about thread safety, then go with vectors.
Class Using List in Java
Create class student.
Having fields Id and name
package listInterface;
import java.util.List;
public class ListClass {
public static void main(String[] args) {
// Defining the list
List<String> alphabets = List.of("A", "B", "C", "D");
System.out.println(alphabets);
}
}
Class to run Student class
Create class StudentClassRunner.
package listInterface;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
// class to custom sorting
class DescendingStudentComparator implements Comparator<Student> {
@Override
public int compare(Student stu1, Student stu2) {
return Integer.compare(stu2.getId(), stu1.getId());
}
}
public class StudentClassRunner {
public static void main(String[] args) {
// TODO Auto-generated method stub
List<Student> students = List.of(new Student(3, "Shubham"), new Student(1, "Ram"), new Student(2, "Krishn"));
List<Student> studentsAl = new ArrayList<>(students);
System.out.println(students.toString());
System.out.println(studentsAl);
// Comparable interface
Collections.sort(studentsAl);
System.out.println(" After sorting Ascending order: ");
System.out.println(studentsAl);
// descending order
// Collections.sort(studentsAl, new DescendingStudentComparator());
// we can call above method also
// or directly we call the sort method
studentsAl.sort(new DescendingStudentComparator());
System.out.println("After sorting DescendingStudentComparator order: ");
System.out.println(studentsAl);
}
}
