Uncovering the Mystery of Missing Tuple2 Class in jdk21

Exploring the Absence of a Built-in Tuple Class in Java and Alternatives for Multi-Value Returns

In my recent adventures with Java programming, I encountered a situation where I needed to return two values from a method. Much to my surprise, despite the language having evolved significantly up to Java 21, there isn’t a built-in Tuple class like I might find in languages such as Python or Scala. This led me down an investigative path: Why doesn’t Java include such a feature, and what are my options for handling multiple return values?

The Quest for a Multi-Return Solution in Java

Initially, I thought of leveraging the javafx.util.Pair available since JDK 8. It seemed to be a straightforward solution as it provides a way to store a pair of values. However, I quickly discovered a snag: this class is part of JavaFX which is not included in the standard Java library from Java 11 onward. To make matters tricky, IntelliJ IDEA, the IDE I frequently use for Java development, required additional configuration or dependency management to adopt JavaFX which I found a bit cumbersome for just one class usage.

Why Java Lacks a Native Tuple Class?

Java has traditionally emphasized clarity and simplicity. The designers might feel that returning multiple values from a method could lead to code that’s harder to understand and maintain. In cases where multiple values are needed, Java encourages the use of custom classes or existing data structures that bundle together multiple elements more explicitly. While this approach may demand more code, it arguably enhances readability and maintains the integrity of data types.

Alternatives to Tuple in Java

Constrained by Java’s standard offerings, I explored several alternatives. Here they are:

1. Custom Data Classes: This is often the most robust option. By creating a class specifically designed for the purpose of holding multiple return values, you maintain strong typing and clear code. For instance, if I needed to return an employee’s name and age, I would create a class EmployeeInfo with these as fields. It aligns well with Java’s object-oriented ethos.

1. Arrays and Collections: For methods that return values of the same type, an array or a collection (like a List) can be used. However, this lacks type safety if the data types are different.

1. Apache Commons Lang Pair and Triple: Instead of JavaFX’s Pair, one can use the Pair or Triple class from the Apache Commons Lang library. These classes are part of a well-maintained, widely used utility library that offers much more beyond simple tuples.

1. Map.Entry: In cases where only two values are needed, implementing Map.Entry<K,V> can serve as a quick and dirty pair class. This is particularly useful if the method semantics intuitively suggest a key-value relationship.

Finishing Thoughts

The journey to find a suitable way to handle multiple return values in Java educated me about the philosophy of Java’s design and offered a fresh appreciation for its strictures. While at times it seems restrictive compared to the flexibility of some other languages, these constraints encourage the development of clean, maintainable code.

I concluded that for my specific needs, I would utilize Apache Commons Lang’s Pair class. It provides a balance between ease of use and functionality without veering too far from Java’s standards. Plus, it saves me from adding JavaFX dependencies solely for one class or writing boilerplate code for a custom class every time I face this issue.

Certainly, the discussion about whether Java should add a native Tuple type continues in the community. But for now, I am quite satisfied with the wealth of third-party libraries and design patterns that compensate for this absence.