A few months ago, I shared an article about what I called Java functional builders, inspired by an equivalent pattern found in Go. The main idea was to have builders that looked like this example:

LanguageModel languageModel = new LanguageModel(
    name("cool-model"),
    project("my-project"),
    temperature(0.5),
    description("This is a generative model")
);

Compared to the more tranditional builder approach:

• You’re using the new keyword again to construct instances.
• There’s no more build() method, which felt a bit verbose.

Compared to using constructors with tons of parameters:

In Java, builders are a pretty classical pattern for creating complex objects with lots of attributes. A nice aspect of builders is that they help reduce the number of constructors you need to create, in particular when not all attributes are required to be set (or if they have default values).

However, I’ve always found builders a bit verbose with their newBuilder() / build() method combos, especially when you work with deeply nested object graphs, leading to lines of code of builders of builders of…