Java Method Extractor

Extracts all method definitions (including body) from .java files found in a given source — either a local directory or a public GitHub repository.

The output is a series of text files, each containing the methods found for a single Java file.

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🛠 Features

• ✅ Recursively collects .java files
• ✅ Parses each file using Eclipse JDT or TreeSitter
• ✅ Extracts all method bodies (with declaration)
• ✅ Outputs one file per method in a .txt format
• ✅ Supports both local directory inspection and GitHub repo cloning in a temporary directory

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🚀 How to Use

Prerequisites

• Java 17 or later: https://jdk.java.net/archive/#:~:text=17.0.2%20(build%2017.0.2%2B8)
• Maven (mvn) to build the project: https://maven.apache.org/download.cgi

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📦 Build the Executable JAR

From the root directory of the project, run:

mvn clean package

Running

After building, you can run the generated JAR with dependencies under the target folder:

From the root directory of the project, run:

java -jar target/java-method-extractor-1.0-jar-with-dependencies.jar <mode> <inputPath> <outputDir>

Mode	Description	Example Input Path
--local	Use a local directory	/home/user/myproject
--github	Clone a public GitHub repo (HTTPS)	https://github.com/user/repo.git

With --github mode, the GitHub repository specified as <inputPath> will be cloned in a temporary directory.

<outputDir> is the path where all the text files will be generated.

outputDir/
├── Main.txt
├── Utils.txt
├── MyClass.txt

You can also specify which parser to use between the Eclipse Compiler for Java and TreeSitter with the respective flags: --ecj or --ts. By default, the Eclipse Compiler for Java is used.

You can also set the minimum number of lines for a method to be extracted with the --ml <number> flag. By default, this is set to 0, meaning all methods will be extracted regardless of their length.

Use the flag --oneline if you wish the output methods to be in a single line.

At the end of the process, the output folder will also contain a performance_metrics.txt file of this format:

Performance Metrics:
--------------------
Total AST Generation Time: 1180195800 ns  ~ 1180.20 ms
Number of AST Generated: 1168
Total Methods Collected: 4945
Total Extraction Time: 131628300 ns ~ 131.63 ms
--of which normalization time: 103878800 ns ~ 103.88 ms