Java: Getting the properties of a class to construct a string representation

You could do:

@Override
public String toString() {
  StringBuilder sb = new StringBuilder();
  sb.append(getClass().getName());
  sb.append(": ");
  for (Field f : getClass().getDeclaredFields()) {
    sb.append(f.getName());
    sb.append("=");
    sb.append(f.get(this));
    sb.append(", ");
  }
  return sb.toString();
}

Don't use string concatenation to construct an end result from 15 data members, particularly if the toString() will be called a lot. The memory fragmentation and overhead could be really high. Use StringBuilder for constructing large dynamic strings.

I usually get my IDE (IntelliJ) to simply generate toString() methods for me rather than using reflection for this.

Another interesting approach is to use the @ToString annotation from Project Lombok:

import lombok.ToString;

@ToString(excludes="id")
public class ToStringExample {
  private static final int STATIC_VAR = 10;
  private String name;
  private Shape shape = new Square(5, 10);
  private String[] tags;
  private int id;

  @ToString(callSuper=true, includeFieldNames=true)
  public static class Square extends Shape {
    private final int width, height;

    public Square(int width, int height) {
      this.width = width;
      this.height = height;
    }
  }
}

I find this much more preferable to, say, Jakarta Commons toString builders because this approach is far more configurable and it's also built at compile-time not run-time.

Check this API org.apache.commons.lang.builder.ToStringBuilder, it provides multiple ways to create toString usinf reflection or without reflection. Take a look at other subclasses as well.