---
language:
- code
license: apache-2.0
task_categories:
- text-generation
tags:
- code
- refactoring
- java
- benchmark
---

# Java Refactoring Benchmark

## Task
Given a Java source file before a refactoring and the refactoring type, produce the refactored file.

## Schema
- `instance_id` — unique identifier
- `repo` — GitHub repo (owner/name)
- `language` — "java"
- `base_commit` — parent SHA (before state)
- `merge_commit` — commit where refactoring was applied
- `refactoring_types` — list of RefactoringMiner type names detected in this commit
- `refactoring_descriptions` — corresponding human-readable descriptions
- `file_path` — primary changed Java file (most lines changed)
- `source_code_before` — full file content before refactoring
- `source_code_after` — full file content after refactoring (ground truth)
- `diff` — full unified diff of the commit (all changed files)
- `is_pure_refactoring` — null = not yet checked; true = no extraneous changes
- `compile_before` / `compile_after` — null = not yet verified
- `PASS_TO_PASS` / `FAIL_TO_PASS` — null = not yet verified
- `created_at` — commit timestamp (ISO 8601)
- `repo_license` — SPDX license of the source repo
- `lines_changed` — total lines changed in the commit

## Split
- `test`: 5857 instances from 23 repos

## Refactoring types
{
  "Change Variable Type": 2443,
  "Add Method Annotation": 2338,
  "Change Return Type": 1690,
  "Change Parameter Type": 1595,
  "Extract Method": 1398,
  "Add Parameter": 1351,
  "Rename Method": 1306,
  "Extract Variable": 1283,
  "Change Method Access Modifier": 1183,
  "Rename Variable": 1089,
  "Remove Method Annotation": 1018,
  "Change Attribute Type": 957,
  "Rename Parameter": 852,
  "Remove Thrown Exception Type": 738,
  "Add Attribute Modifier": 656,
  "Remove Parameter": 611,
  "Inline Variable": 595,
  "Extract And Move Method": 586,
  "Change Attribute Access Modifier": 572,
  "Rename Attribute": 517,
  "Move Method": 510,
  "Add Class Annotation": 419,
  "Pull Up Method": 392,
  "Encapsulate Attribute": 310,
  "Modify Method Annotation": 287,
  "Move Class": 282,
  "Add Attribute Annotation": 270,
  "Add Method Modifier": 263,
  "Add Thrown Exception Type": 238,
  "Rename Class": 235,
  "Change Class Access Modifier": 224,
  "Modify Class Annotation": 213,
  "Replace Variable With Attribute": 212,
  "Remove Attribute Modifier": 211,
  "Inline Method": 207,
  "Move Code": 196,
  "Remove Class Annotation": 192,
  "Parameterize Variable": 186,
  "Add Parameter Modifier": 185,
  "Pull Up Attribute": 182,
  "Invert Condition": 175,
  "Remove Method Modifier": 174,
  "Add Parameter Annotation": 168,
  "Move Attribute": 155,
  "Extract Attribute": 154,
  "Add Variable Modifier": 148,
  "Extract Class": 144,
  "Remove Attribute Annotation": 142,
  "Move And Rename Method": 133,
  "Change Thrown Exception Type": 128,
  "Move And Inline Method": 128,
  "Push Down Method": 127,
  "Remove Parameter Modifier": 109,
  "Assert Throws": 105,
  "Remove Parameter Annotation": 90,
  "Replace Generic With Diamond": 90,
  "Replace Attribute With Variable": 84,
  "Move And Rename Class": 81,
  "Move Source Folder": 81,
  "Localize Parameter": 80,
  "Merge Conditional": 80,
  "Add Class Modifier": 71,
  "Split Conditional": 70,
  "Replace Anonymous With Lambda": 59,
  "Remove Class Modifier": 57,
  "Extract Superclass": 56,
  "Remove Variable Modifier": 55,
  "Extract Fixture": 52,
  "Replace Conditional With Ternary": 48,
  "Inline Attribute": 43,
  "Modify Attribute Annotation": 41,
  "Replace Anonymous With Class": 37,
  "Try With Resources": 32,
  "Change Type Declaration Kind": 31,
  "Merge Parameter": 28,
  "Push Down Attribute": 25,
  "Extract Interface": 24,
  "Parameterize Attribute": 23,
  "Reorder Parameter": 23,
  "Split Parameter": 20,
  "Split Method": 16,
  "Rename Package": 14,
  "Merge Variable": 14,
  "Move And Rename Attribute": 13,
  "Extract Subclass": 12,
  "Move Package": 11,
  "Replace Loop With Pipeline": 10,
  "Replace Pipeline With Loop": 10,
  "Parameterize Test": 9,
  "Remove Variable Annotation": 9,
  "Merge Attribute": 9,
  "Merge Catch": 9,
  "Split Attribute": 8,
  "Add Variable Annotation": 7,
  "Modify Parameter Annotation": 6,
  "Replace Conditional With Assumption": 6,
  "Merge Class": 5,
  "Replace Attribute": 5,
  "Collapse Hierarchy": 4,
  "Merge Method": 3,
  "Split Class": 2,
  "Split Variable": 1
}

## Detection
Mined using RefactoringMiner 3.1.3.