Let's assume that we have the following Melon class and List of Melon:

public class Melon {

  private final String type;
  private int weight;

  public static int growing100g(Melon melon) {
    melon.setWeight(melon.getWeight() + 100);

    return melon.getWeight();
  }

  // constructors, getters, setters, equals(),
  // hashCode(), toString() omitted for brevity
}

List<Melon> melons = Arrays.asList(
  new Melon("Crenshaw", 1200), new Melon("Gac", 3000),
  new Melon("Hemi", 2600), new Melon("Hemi", 1600));

In a nutshell, method references are shortcuts for lambda expressions.

Mainly, method reference is a technique that's used to call a method by name rather than by a description of how to call it. The main benefit is readability.

A method reference is written by placing the target reference before the delimiter, ::, and the name of the method is provided after it.

We'll take a look at all four kinds of method references in the upcoming sections.