Android: Why does the Color class have a public constructor?

Question

Why does the android Color class have a public constructor when all its members are static? Is it just a mistake?

Answer 1

Probably consistency and potential future use are reasons for the engineer to write a constructor even if it does nothing. But, the engineer may not have written the constructor. A default public constructor is created by the compiler if no constructor is given.

See the answer given here. It links to this.

The documentation, which is probably auto-generated to some extent, might inform you of the default constructors' existence, even if the engineer did not create it.

Answer 2

The source code for the Color.java file shows that no Google engineer explicitly wrote a public constructor for the Color class.

The API documentation for the Color class does list a public constructor, but Java has an implicit default constructor, and that is the constructor listed in the documentation.

The real possible questions here are either/or,

• Why does the Google Android documentation list implicit default constructors in the constructor section of class documentation?
• Why does Java have an implicit default constructor when I could possibly make a class that only has static members?

For the first point I don't think that is any mistake or a bad design decision of Google to decide to list the implicit default constructor. They could define a constructor in the class to restrict access to any constructors, but that would just require extra code, and uselessly creating a default constructor for a class that only has static members does not cause any misuse of the class.

For the second point it might make sense to have a compiler optimization to prevent any implicit default constructors in classes that have only static members, but that's a question for another thread.

tl;dr Nope, not a mistake.