[java] incorrect generation of java Object

Description

"Attributes" : {
  "type" : "object"
},

package com.macomp;
import java.util.Objects;
@javax.annotation.Generated(value = "class io.swagger.codegen.languages.JavaClientCodegen", date = "2016-04-14T08:31:30.310-07:00")
public class Attributes   {

  @Override
  public boolean equals(Object o) {
      if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    Attributes attributes = (Attributes) o;
    return true;
  }

  @Override
  public int hashCode() {
    return Objects.hash();
  }

  @Override
  public String toString() {
    StringBuilder sb = new StringBuilder();
   sb.append("class Attributes {\n");

   sb.append("}");
   return sb.toString();
  }

  /**
   * Convert the given object to string with each line indented by 4 spaces
   * (except the first line).
   */
  private String toIndentedString(Object o) {
    if (o == null) {
      return "null";
    }
    return o.toString().replace("\n", "\n    ");
  }
}

Contributor guide

Tech stack

java

Domain

backendtooling

Issue type

bug

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

3

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

1-3 hours

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

stale

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

clear

Prerequisites

JavaSwagger/OpenAPIbasic code generation concepts

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

40

Research direction

The issue reports that an empty object in Swagger spec ('Attributes' with type 'object' and no properties) is incorrectly generated as a new class instead of being mapped to java.lang.Object. Investigate the Swagger codegen's model generation logic in the Java client codegen, specifically the handling of objects with no properties. Look at the template files for Java model classes to see if there is a condition to skip generating a class for empty objects. Check for existing tests and consider adding a fix that outputs Object type when the object has no properties.