Java constructor with large arguments or Java bean getter/setter approach

Question

I can\'t decide which approach is better for creating objects with a large number of fields (10+) (all mandatory) the constructor approach of the getter/setter. Constructor

Answer 1

I would implement the builder pattern like this:

package so1632058;

public class MyClass {
  private final String param1;
  private final String param2;

  MyClass(Builder builder) {
    this.param1 = builder.param1;
    this.param2 = builder.param2;
  }

  public String getParam1() {
    return param1;
  }

  public String getParam2() {
    return param2;
  }

  @SuppressWarnings("hiding")
  public static final class Builder {
    String param1;
    String param2;

    public Builder param1(String param1) {
      this.param1 = param1;
      return this;
    }

    public Builder param2(String param2) {
      this.param2 = param2;
      return this;
    }

    public MyClass toMyClass() {
      return new MyClass(this);
    }
  }
}

And then have the following code to use it:

package so1632058;

public class Main {

  public static void main(String[] args) {
    MyClass.Builder builder = new MyClass.Builder();
    builder.param1("p1").param2("p2");
    MyClass instance = builder.toMyClass();
    instance.toString();
  }

}

Some notes:

• There are no methods with many parameters.
• The additional checking can be done in the MyClass constructor.
• I made the constructor's visibility package-wide to avoid the "synthetic-access" warning.
• Same for the builder's instance fields.
• The only way to construct an instance of MyClass is via the Builder.