ObjectB class described in http://www.dassiorleando.xyz/safely-tostring-a-java-object

ObjectB.java

public class ObjectB {
    private String propB;
 
    public ObjectB(String propB) {
        this.propB = propB;
    }
 
    // Getters and setters
 
    @Override
    public String toString() {
        return "ObjectB{" +
                "propB='" + propB + '\'' +
                '}';
    }
}