How to Search for Strings in an ArrayList of Custom Objects in Java?

How can I search for specific string values in an ArrayList containing custom objects in Java?

public class Datapoint implements Serializable {
  private String name;
  // Other fields and methods...
}

In Java, searching for specific strings within an ArrayList that holds custom objects involves iterating through the objects and comparing the desired string against the object's properties. Here’s a detailed guide on how to implement this search functionality.

import java.util.ArrayList;
import java.util.List;

public class Datapoint {
    private String name;

    public Datapoint(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }
}

public class Main {
    public static void main(String[] args) {
        List<Datapoint> dataPoints = new ArrayList<>();
        dataPoints.add(new Datapoint("Alpha"));
        dataPoints.add(new Datapoint("Bravo"));
      
        String search = "Al";
        for (Datapoint dp : dataPoints) {
            if (dp.getName().contains(search)) {
                System.out.println("Found: " + dp.getName());
            }
        }
    }
}

Causes

• The need to search for certain attribute values in a list of objects.
• ArrayLists do not have built-in search features for custom object attributes.

Solutions

• Implement a method to iterate through the ArrayList and check each object's attributes against the target string.
• Use Java Streams for a more concise and modern approach.

Mistake: Not overriding 'toString()' for custom object display

Solution: Override the 'toString()' method to provide a meaningful representation of your object.

Mistake: Not checking for null values in properties

Solution: Always check for null before calling methods on properties to avoid NullPointerException.