#1

[Auraliano]

public class DataHolder {
public final String data;

public DataHolder(String data) {
    this.data = data;
}

}

If it has many properties , create many construct method ? it similar to use get()/set() way

[Ghost141]

Then you probably should consider the builder pattern. https://github.com/cxxr/better-java#the-builder-pattern

[Auraliano]

Builder pattern can resolve this question,But If it only has one attribute, why do you need to create a class?

[cxxr]

In Java, everything is an object.

[Auraliano]

If a class includes only one string attribute ,Why not use string directly?

[Hinsteny]

Maybe we can use 'Optional' in java8!

[cxxr]

It was an example.