### Core Repository Configuration Example

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

An example of the [core] section in a Git configuration file.

```ini
[core]
    repositoryformatversion = 0
    filemode = true
    bare = false
    logallrefupdates = true
```

--------------------------------

### User Identity Configuration Example

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

An example of the [user] section in a Git configuration file.

```ini
[user]
    name = John Doe
    email = john@example.com
```

--------------------------------

### Documentation Structure Example

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/README.md

Illustrates the standard structure for each API reference file, including component and method details, parameters, return types, exceptions, usage examples, and source locations.

```markdown
## Component Name
  
### Method/Class Name
  - Full signature
  - Parameters table (name | type | required | default | description)
  - Return type
  - Throws (error conditions)
  - Usage example
  - Source location
```

--------------------------------

### Remote Repository Configuration Example

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

Examples of [remote "origin"] and [remote "upstream"] sections in a Git configuration file, specifying URLs and fetch refspecs.

```ini
[remote "origin"]
    url = https://github.com/user/repo.git
    fetch = +refs/heads/*:refs/remotes/origin/*

[remote "upstream"]
    url = https://github.com/upstream/repo.git
    fetch = +refs/heads/*:refs/remotes/upstream/*
```

--------------------------------

### Opening a JGit Repository

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/README.md

This is the starting point for most JGit operations. It demonstrates how to open an existing JGit repository.

```java
Repository repo = CookbookHelper.openJGitCookbookRepository();
```

--------------------------------

### Branch Configuration Example

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

Examples of [branch "master"] and [branch "develop"] sections in a Git configuration file, specifying the remote and merge upstream branch.

```ini
[branch "master"]
    remote = origin
    merge = refs/heads/master

[branch "develop"]
    remote = origin
    merge = refs/heads/develop
```

--------------------------------

### Configure and Start Jetty HTTP Server with GitServlet

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/05-http-server.md

Configures and starts a Jetty web server on port 8080. It sets up a context handler and registers the GitServlet to handle requests at the /repo/* path, enabling Git operations over HTTP.

```Java
Server server = new Server(8080);

ServletContextHandler context = 
    new ServletContextHandler(ServletContextHandler.SESSIONS);
context.setContextPath("/");
server.setHandler(context);

context.addServlet(gs, "/repo/*");

server.start();
return server;
```

--------------------------------

### Gradle Run Command

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/05-http-server.md

Execute the Gradle run task to start the HTTP server application.

```bash
cd httpserver
./gradlew run
```

--------------------------------

### Clone Command Line Example

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/05-http-server.md

Standard git command to clone a repository from an HTTP URL. Replace 'some_repo' with the actual repository name.

```bash
git clone http://localhost:8080/repo/some_repo
```

--------------------------------

### Configure HTTP Protocol Settings

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

Example INI file configuration for the HTTP protocol section in JGit.

```ini
[http]
    receivepack = true
    uploadpack = true
    sslVerify = true
```

--------------------------------

### Basic Repository Resolver Setup

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/05-http-server.md

Sets a basic repository resolver for the GitServlet that always returns the same repository instance and increments its open count.

```java
GitServlet gs = new GitServlet();
gs.setRepositoryResolver((req, name) -> {
    repository.incrementOpen();
    return repository;
});
```

--------------------------------

### Implementing a Cancellable Progress Monitor

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/errors.md

Provides an example of a custom ProgressMonitor implementation that allows for operation cancellation.

```java
class SmartProgressMonitor implements ProgressMonitor {
    private volatile boolean cancelled = false;
    
    @Override
    public boolean isCancelled() {
        return cancelled;
    }
    
    public void requestCancel() {
        cancelled = true;
    }
}

SmartProgressMonitor monitor = new SmartProgressMonitor();
try {
    git.fetch().setProgressMonitor(monitor).call();
} catch (CanceledException e) {
    System.out.println("Operation cancelled");
}
```

--------------------------------

### Open JGit Repository

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/INDEX.md

Opens an existing JGit repository. This is a helper method for cookbook examples.

```java
CookbookHelper.openJGitCookbookRepository()
```

--------------------------------

### Push Command Line Example

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/05-http-server.md

Standard git command to push local changes to the 'origin' remote, specifically for the 'master' branch. Requires server-side configuration for write operations.

```bash
git push origin master
```

--------------------------------

### Configure ServletContextHandler with GitServlet

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/05-http-server.md

Configure a ServletContextHandler to serve Git operations under a specific context path. This example adds a SecurityFilter and the GitServlet.

```java
ServletContextHandler context = new ServletContextHandler();
context.setContextPath("/");

// Add security filter
context.addFilter(new FilterHolder(new SecurityFilter()), "/*", 
                   EnumSet.of(DispatcherType.REQUEST));

// Add GitServlet
context.addServlet(gs, "/git/*");

server.setHandler(context);
```

--------------------------------

### Basic HTTP Basic Authentication Handler

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/05-http-server.md

Provides a basic example of how to check for the Authorization header in an HTTP request to implement authentication. Returns a 401 if the header is missing.

```java
// Custom handler for HTTP Basic Auth
String auth = request.getHeader("Authorization");
if (auth == null) {
    // Return 401
}
```

--------------------------------

### List All Commits in a Repository

Source: https://github.com/centic9/jgit-cookbook/blob/master/README.md

Walks through all commits in the repository history, starting from the tips of all references. This is a more comprehensive log than 'git log'.

```java
import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.errors.RevisionSyntaxException;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.errors.AmbiguousObjectException;
import org.eclipse.jgit.api.errors.GitAPIException;
import java.io.File;
import java.io.IOException;

public class WalkAllCommits {

    public static void main(String[] args) throws IOException, GitAPIException {
        File repoPath = new File("my_repo"); // Replace with your repository path

        try (Repository repository = org.eclipse.jgit.storage.file.FileRepositoryBuilder.create(new org.eclipse.jgit.lib.FileRepository(new File(repoPath, ".git")))) {
            try (RevWalk walk = new RevWalk(repository)) {
                // Get the HEAD commit
                ObjectId head = repository.resolve("HEAD");
                if (head == null) {
                    System.out.println("Repository is empty or HEAD is not set.");
                    return;
                }
                RevCommit commit = walk.parseCommit(head);

                // Iterate through all commits reachable from HEAD
                walk.markStart(walk.parseCommit(repository.resolve("HEAD")));
                for (RevCommit revCommit : walk) {
                    System.out.println("Commit: " + revCommit.getId().getName());
                    System.out.println("Author: " + revCommit.getAuthorIdent().getName());
                    System.out.println("Date: " + revCommit.getAuthorIdent().getWhen());
                    System.out.println("Message: " + revCommit.getShortMessage());
                    System.out.println("--------------------");
                }
            }
        }
    }
}
```

--------------------------------

### Handling Specific Git Exceptions

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/README.md

This example shows how to catch specific JGit exceptions to handle different error scenarios gracefully, such as an empty repository or a missing reference.

```java
catch (NoHeadException e) { /* empty repository */ }
catch (RefNotFoundException e) { /* missing ref */ }
catch (GitAPIException e) { /* other git error */ }
```

--------------------------------

### Custom Multi-Repository Resolver

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/05-http-server.md

Implement a custom RepositoryResolver to support multiple repositories based on a base directory. This example locates repositories by appending '.git' to the provided name within the base directory.

```java
class MultiRepoResolver implements RepositoryResolver<HttpServletRequest> {
    private File baseDir;
    
    @Override
    public Repository open(HttpServletRequest req, String name) {
        File repoDir = new File(baseDir, name + ".git");
        if (!repoDir.exists()) {
            throw new RepositoryNotFoundException(name);
        }
        
        Repository repo = new FileRepositoryBuilder()
            .setGitDir(repoDir)
            .build();
        repo.incrementOpen();
        return repo;
    }
}
```

--------------------------------

### Create New Repository From Scratch

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/03-porcelain-basic.md

Demonstrates the process of creating a completely new Git repository from the ground up. This is useful for setting up a repository for the first time.

```java
try (Repository repository = CookbookHelper.createNewRepository()) {
    try (Git git = new Git(repository)) {
        // Use the repository
    }
}
```

--------------------------------

### Initialize Repository Builder

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/overview.md

Demonstrates how to initialize a FileRepositoryBuilder to find and build a Git repository.

```java
FileRepositoryBuilder builder = new FileRepositoryBuilder();
Repository repository = builder
    .readEnvironment()
    .findGitDir()
    .build();
```

--------------------------------

### SimpleProgressMonitor Start Task

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/01-helpers.md

Signals the start of work on multiple tasks for the SimpleProgressMonitor. This method should be called once at the beginning of a batch operation.

```java
public void start(int totalTasks)
```

--------------------------------

### Populate Git Repository with Sample Data

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/05-http-server.md

Populates an existing Git repository by creating a test file, adding it to the index, and making an initial commit. This snippet also configures the repository to allow HTTP push operations.

```Java
repository.getConfig().setString("http", null, "receivepack", "true");
```

```Java
try (Git git = new Git(repository)) {
    File myfile = new File(repository.getDirectory().getParent(), "testfile");
    if(!myfile.createNewFile()) {
        throw new IOException("Could not create file " + myfile);
    }
    
    git.add().addFilepattern("testfile").call();
    
    System.out.println("Added file " + myfile + " to repository at " + 
                       repository.getDirectory());
    
    git.commit().setMessage("Test-Checkin").call();
}
```

--------------------------------

### Iterate Commits Starting from a Reference

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/02-lowlevel-api.md

Uses RevWalk to iterate over all commits reachable from a specified starting point. This is fundamental for traversing commit history.

```java
try (RevWalk walk = new RevWalk(repository)) {
    RevCommit start = walk.parseCommit(headRef.getObjectId());
    walk.markStart(start);
    
    for (RevCommit commit : walk) {
        System.out.println("Commit: " + commit.getName());
    }
}
```

--------------------------------

### Iterate Through Commit History

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/types.md

Use RevWalk to traverse the commit graph starting from a specific commit. Mark start points and iterate to process each commit.

```java
try (RevWalk walk = new RevWalk(repository)) {
    RevCommit start = walk.parseCommit(startId);
    walk.markStart(start);
    
    for (RevCommit commit : walk) {
        System.out.println(commit.getFullMessage());
    }
}
```

--------------------------------

### Initialize a New Git Repository

Source: https://github.com/centic9/jgit-cookbook/blob/master/README.md

Use this to create a new, empty Git repository. Ensure the directory exists before initialization.

```java
import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.api.errors.GitAPIException;
import java.io.File;
import java.io.IOException;

public class InitRepository {

    public static void main(String[] args) throws IOException, GitAPIException {
        // Create a new repository here
        File repoPath = new File("my_new_repo");
        if (!repoPath.exists()) {
            repoPath.mkdirs();
        }

        // Initialize the repository
        try (Git git = Git.init().setDirectory(repoPath).call()) {
            System.out.println("Initialized empty Git repository in " + repoPath.getAbsolutePath());
        }
    }
}
```

--------------------------------

### Build Repository with Environment and GitDir Search

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/types.md

Construct a Repository instance by reading environment variables and searching parent directories for the .git directory. This pattern is useful for flexible repository location.

```java
FileRepositoryBuilder builder = new FileRepositoryBuilder();
try (Repository repository = builder
        .readEnvironment()
        .findGitDir()
        .build()) {
    // Use repository
}
```

--------------------------------

### Get Ref

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/INDEX.md

Retrieves a Git reference object by its name using the low-level API.

```java
repository.getRef(String)
```

--------------------------------

### Set GIT_WORK_TREE Environment Variable

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

Example of setting GIT_DIR and GIT_WORK_TREE environment variables in bash.

```bash
export GIT_DIR=/path/to/.git
export GIT_WORK_TREE=/path/to/working/tree
```

--------------------------------

### Resource Management with Try-with-Resources

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/errors.md

Shows how to ensure resources like Repository, Git, and RevWalk are automatically closed, even if exceptions occur.

```java
try (Repository repo = openRepository();
     Git git = new Git(repo);
     RevWalk walk = new RevWalk(repo)) {
    // Operations
} catch (IOException e) {
    // Resources automatically closed even on error
}
```

--------------------------------

### CreateNewRepository

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/03-porcelain-basic.md

Demonstrates creating a completely new Git repository from scratch using JGit.

```APIDOC
## CreateNewRepository

### Description
Demonstrates creating a completely new repository from scratch.

### Usage Pattern
```java
try (Repository repository = CookbookHelper.createNewRepository()) {
    try (Git git = new Git(repository)) {
        // Use the repository
    }
}
```
```

--------------------------------

### Set GIT_DIR Environment Variable

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

Example of setting the GIT_DIR environment variable in bash for JGit.

```bash
export GIT_DIR=/path/to/.git
java -jar application.jar
```

--------------------------------

### Recover from Missing Repository

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/errors.md

Demonstrates creating a new repository if an IOException occurs during the attempt to open an existing one. Useful for scenarios where a repository might not yet exist.

```java
try {
    Repository repo = CookbookHelper.openJGitCookbookRepository();
} catch (IOException e) {
    // Create new repository instead
    repo = CookbookHelper.createNewRepository();
}
```

--------------------------------

### Open Existing Git Repository with JGit

Source: https://github.com/centic9/jgit-cookbook/blob/master/README.md

Demonstrates how to open an existing Git repository using JGit. Ensure the repository path is valid.

```Java
package org.dstadler.jgit;

import java.io.File;
import java.io.IOException;

import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.storage.file.FileRepositoryBuilder;

public class OpenRepository {

	public static void main(String[] args) {
		Repository repository = null;
		try {
			// build repository
			FileRepositoryBuilder builder = new FileRepositoryBuilder();
			repository = builder.setGitDir(new File(".git")) // sets the directory for the .git folder
					.readEnvironment() // scan environment GIT_DIR, GIT_WORK_TREE, ...
					.findCommonDir() // find the common directory for the .git folder
					.build();

			System.out.println("Opened repository at " + repository.getDirectory());
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			if (repository != null) {
				repository.close();
			}
		}
	}
}
```

--------------------------------

### Retrieve an exact Ref

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/types.md

Get a specific reference by its full name, ensuring an exact match.

```java
Ref exactRef = repository.exactRef("refs/heads/master");
```

--------------------------------

### InitRepository

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/03-porcelain-basic.md

Initializes a new Git repository in an existing directory. This is the high-level equivalent of `git init`.

```APIDOC
## InitRepository

### Description
Initializes a new Git repository in an existing directory.

### Usage Pattern
```java
InitCommand init = Git.init()
    .setDirectory(new File("/path/to/repo"));
try (Git git = init.call()) {
    // Repository is now initialized
}
```

### Equivalent Git Command
`git init`
```

--------------------------------

### Direct FileRepositoryBuilder Usage

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/01-helpers.md

Demonstrates the direct usage of FileRepositoryBuilder for more granular control when setting up a repository. Reads environment variables and builds the repository.

```java
FileRepositoryBuilder builder = new FileRepositoryBuilder();
try (Repository repository = builder.setGitDir(new File(".git"))
        .readEnvironment()
        .build()) {
    // Use repository
}
```

--------------------------------

### Create New JGit Repository

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/INDEX.md

Creates a new JGit repository. This is a helper method for cookbook examples.

```java
CookbookHelper.createNewRepository()
```

--------------------------------

### Create and Delete Branches

Source: https://github.com/centic9/jgit-cookbook/blob/master/README.md

Demonstrates how to create a new branch and delete an existing one. Ensure the branch to be deleted is not the current HEAD.

```java
import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.api.errors.GitAPIException;
import java.io.File;
import java.io.IOException;

public class CreateAndDeleteBranch {

    public static void main(String[] args) throws IOException, GitAPIException {
        File repoPath = new File("my_repo"); // Replace with your repository path
        String newBranchName = "my-new-branch";
        String branchToDelete = "my-old-branch";

        try (Git git = Git.open(repoPath)) {
            // Create a new branch
            git.branchCreate().setName(newBranchName).call();
            System.out.println("Branch '" + newBranchName + "' created.");

            // Delete a branch (ensure it's not the current branch)
            // git.branchDelete().setBranchNames(branchToDelete).call();
            // System.out.println("Branch '" + branchToDelete + "' deleted.");
        }
    }
}
```

--------------------------------

### Get ObjectId Name and Abbreviated Form

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/types.md

Retrieve the full hexadecimal name and an abbreviated form of an ObjectId.

```java
String hex = id.getName();
String short = id.abbreviate(7).name();
```

--------------------------------

### Retrieve a specific Ref

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/types.md

Get a specific reference (like a branch or tag) from the repository by its full name.

```java
Ref ref = repository.getRef("refs/heads/master");
```

--------------------------------

### Use Try-with-Resources for Repository Management

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/overview.md

Illustrates the use of try-with-resources for ensuring proper management and closing of a Git repository.

```java
try (Repository repository = ...) {
    // Use repository
}
```

--------------------------------

### Set GIT_SSH_COMMAND Environment Variable

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

Example of setting the GIT_SSH_COMMAND environment variable in bash with custom SSH options.

```bash
export GIT_SSH_COMMAND="ssh -i ~/.ssh/custom_key -o StrictHostKeyChecking=no"
```

--------------------------------

### Chaining Exceptions to Get Underlying Cause

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/errors.md

Demonstrates how to inspect the cause of a GitAPIException to retrieve more detailed error information.

```java
try {
    doGitOperation();
} catch (GitAPIException e) {
    if (e.getCause() != null) {
        // Underlying cause may provide more detail
        System.err.println("Caused by: " + e.getCause().getMessage());
    }
}
```

--------------------------------

### Enable Push over HTTP Configuration

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

Configure the repository to allow pushing over HTTP. Ensure this setting is used cautiously and with appropriate security measures.

```java
repository.getConfig().setString("http", null, "receivepack", "true");
repository.getConfig().save();
```

--------------------------------

### Recursive Tree Walk

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/types.md

Iterate through all entries in a repository's tree recursively. Ensure the repository and commit are valid before starting.

```java
try (TreeWalk walk = new TreeWalk(repository)) {
    walk.addTree(commit.getTree());
    walk.setRecursive(true);
    
    while (walk.next()) {
        String path = walk.getPathString();
        System.out.println(path);
    }
}
```

--------------------------------

### Accessing Core Repository Configuration

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

Demonstrates reading boolean values for core repository settings like filemode and bare repository status, and setting the ignorecase option.

```java
boolean fileMode = config.getBoolean("core", null, "filemode", true);
boolean bare = config.getBoolean("core", null, "bare", false);

config.setBoolean("core", null, "ignorecase", true);
```

--------------------------------

### Set GIT_CONFIG Environment Variable

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

Example of setting the GIT_CONFIG environment variable in bash to specify an additional config file path.

```bash
export GIT_CONFIG=/etc/git/config.local
```

--------------------------------

### Create, List, Apply, and Drop Stashes

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/04-porcelain-remote.md

Demonstrates how to manage stashed changes in a Git repository using JGit's Porcelain API. This includes creating a stash, listing existing stashes, applying a stash without removing it, and applying and then dropping a stash.

```java
try (Git git = new Git(repository)) {
    // Stash current changes
    RevCommit stash = git.stashCreate().call();
    System.out.println("Stashed: " + stash);
    
    // List stashes
    List<RevCommit> stashList = git.stashList().call();
    for (RevCommit commit : stashList) {
        System.out.println("Stash: " + commit.getShortMessage());
    }
    
    // Apply stash (keeps it)
    git.stashApply()
        .setStashRef(0)  // Apply first stash
        .call();
    
    // Pop stash (applies and removes)
    RevCommit popped = git.stashApply()
        .setStashRef(0)
        .call();
    git.stashDrop()
        .setStashRef(0)
        .call();
}
```

--------------------------------

### Configure Git.cloneRepository() in JGit

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

Demonstrates the configuration options available for cloning a repository using JGit's command builder.

```java
Git.cloneRepository()
    .setURI(String)                        // Remote URL (required)
    .setDirectory(File)                    // Clone destination (required)
    .setBranch(String)                     // Specific branch (default: remote default)
    .setCloneAllBranches(boolean)          // Clone all branches
    .setNoCheckout(boolean)                // Skip working tree checkout
    .setDepth(int)                         // Shallow clone depth
    .setProgressMonitor(ProgressMonitor)   // Progress tracking
    .setCredentialsProvider(CredentialsProvider)  // Authentication
    .setTimeout(int)                       // Network timeout (seconds)
    .call()
```

--------------------------------

### Walk Commits Between Two References

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/02-lowlevel-api.md

Iterates through commits that are present in a starting reference but not in an ending reference. This is useful for finding differences between branches.

```java
try (RevWalk walk = new RevWalk(repository)) {
    RevCommit start = walk.parseCommit(repository.resolve("master"));
    RevCommit end = walk.parseCommit(repository.resolve("develop"));
    
    walk.markStart(start);
    walk.markUninteresting(end);  // Exclude this and its ancestors
    
    for (RevCommit commit : walk) {
        // Commits in master but not in develop
    }
}
```

--------------------------------

### Accessing User Identity Configuration

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

Shows how to read and set the user's name, email, and signing key from the [user] configuration section.

```java
String name = config.getString("user", null, "name");
String email = config.getString("user", null, "email");

config.setString("user", null, "name", "John Doe");
config.setString("user", null, "email", "john@example.com");
config.save();
```

--------------------------------

### Create New Git Repository with JGit

Source: https://github.com/centic9/jgit-cookbook/blob/master/README.md

Demonstrates how to create a new Git repository using JGit. This will create a new .git directory in the specified path.

```Java
package org.dstadler.jgit;

import java.io.File;
import java.io.IOException;

import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.lib.Repository;

public class CreateNewRepository {

	public static void main(String[] args) {
		// Define the path for the new repository
		File repoPath = new File("new-repo");

		try (Repository repository = Git.init().setDirectory(repoPath).call().getRepository()) {
			System.out.println("Created new repository at " + repository.getDirectory());
		} catch (IOException | GitAPIException e) {
			e.printStackTrace();
		}
	}
}
```

--------------------------------

### Get SHA-1 Ref from Name (Java)

Source: https://github.com/centic9/jgit-cookbook/blob/master/README.md

Retrieves the SHA-1 identifier for a given Git reference name, such as 'refs/heads/master'. Requires a JGit Repository object.

```Java
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.storage.file.FileRepositoryBuilder;

import java.io.IOException;

public class GetRefFromName {

    public static void main(String[] args) throws IOException {
        try (Repository repository = new FileRepositoryBuilder()
                .setGitDir(new java.io.File(".git"))
                .readEnvironment()
                .findGitDir()
                .build()) {

            String refName = "refs/heads/master";
            Ref ref = repository.findRef(refName);

            if (ref != null) {
                System.out.println("SHA-1 for " + refName + ": " + ref.getObjectId().getName());
            } else {
                System.out.println("Ref " + refName + " not found.");
            }
        }
    }
}
```

--------------------------------

### Accessing Branch Configuration

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

Demonstrates reading and setting the default remote and merge branch for a specific local branch.

```java
String remote = config.getString("branch", "develop", "remote");
String merge = config.getString("branch", "develop", "merge");

config.setString("branch", "develop", "remote", "origin");
config.setString("branch", "develop", "merge", "refs/heads/develop");
config.save();
```

--------------------------------

### Custom Authenticating Repository Resolver

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/05-http-server.md

Implement a custom RepositoryResolver to add authentication to repository access. This example checks for a valid Authorization header before opening a repository.

```java
class AuthenticatingRepositoryResolver implements RepositoryResolver<HttpServletRequest> {
    @Override
    public Repository open(HttpServletRequest req, String name) 
            throws RepositoryNotFoundException, ServiceNotEnabledException {
        
        String auth = req.getHeader("Authorization");
        if (!isValidAuth(auth)) {
            throw new ServiceNotEnabledException();
        }
        
        Repository repo = getRepository(name);
        repo.incrementOpen();
        return repo;
    }
}
```

--------------------------------

### Configure Git.log() in JGit

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

Demonstrates the configuration options available for retrieving commit logs using JGit's command builder.

```java
git.log()
    .add(ObjectId)                         // Include commits from ref
    .not(ObjectId)                         // Exclude commits from ref
    .all()                                 // Include all refs
    .addPath(String)                       // Filter by file path
    .setMaxCount(int)                      // Limit results
    .setSkip(int)                          // Skip first N commits
    .setAuthor(String)                     // Filter by author (regex)
    .setCommitter(String)                  // Filter by committer (regex)
    .since(Date)                           // Commits after date
    .until(Date)                           // Commits before date
    .call()
```

--------------------------------

### Common Java Imports for Git Server

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/05-http-server.md

Essential import statements for building a Git HTTP server using Jetty and JGit.

```java
import org.eclipse.jetty.ee10.servlet.ServletContextHandler;
import org.eclipse.jetty.server.Server;
import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.http.server.GitServlet;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.storage.file.FileRepositoryBuilder;

import java.io.File;
import java.io.IOException;
```

--------------------------------

### Get Blame Information for a File

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/04-porcelain-remote.md

Determines which commit last modified each line of a specified file. This is useful for understanding the history and authorship of specific lines of code.

```java
try (Git git = new Git(repository)) {
    BlameResult blameResult = git.blame()
        .setFilePath("src/Main.java")
        .call();
    
    for (int i = 0; i < blameResult.getResultSize(); i++) {
        RevCommit commit = blameResult.getSourceCommit(i);
        String author = commit.getAuthorIdent().getName();
        String line = blameResult.getResultContents().getString(i);
        
        System.out.printf("%s: %s%n", author, line);
    }
}
```

--------------------------------

### Get Git Reference by Name

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/02-lowlevel-api.md

Retrieves a Git reference (Ref) object for a given reference string like 'refs/heads/master'. Use exactRef for an exact match.

```Java
try (Repository repository = CookbookHelper.openJGitCookbookRepository()) {
    Ref head = repository.exactRef("refs/heads/master");
    System.out.println("Ref: " + head.getName() + " -> " + head.getObjectId().getName());
}
```

--------------------------------

### Handling Empty Repository Exception

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/errors.md

Demonstrates catching NoHeadException for an empty repository and returning an empty list.

```java
try (Git git = new Git(repository)) {
    return git.log().call();
} catch (NoHeadException e) {
    System.out.println("Repository is empty. Create initial commit first.");
    return Collections.emptyList();
}
```

--------------------------------

### Get Commit Message (Java)

Source: https://github.com/centic9/jgit-cookbook/blob/master/README.md

Extracts the commit message from a given commit object. This requires a RevCommit object, which can be obtained using methods like `repository.parseCommit()`.

```Java
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.storage.file.FileRepositoryBuilder;
import org.eclipse.jgit.revwalk.RevWalk;

import java.io.IOException;

public class GetCommitMessage {

    public static void main(String[] args) throws IOException {
        try (Repository repository = new FileRepositoryBuilder()
                .setGitDir(new java.io.File(".git"))
                .readEnvironment()
                .findGitDir()
                .build()) {

            String commitIdString = "HEAD"; // or a SHA-1 string
            ObjectId commitId = repository.resolve(commitIdString);

            if (commitId != null) {
                try (RevWalk revWalk = new RevWalk(repository)) {
                    RevCommit commit = revWalk.parseCommit(commitId);
                    System.out.println("Commit Message: " + commit.getFullMessage());
                }
            } else {
                System.out.println("Commit " + commitIdString + " not found.");
            }
        }
    }
}
```

--------------------------------

### Handle Temporary File Creation Failure

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/errors.md

Illustrates how to handle errors during temporary file or directory creation. This code checks for deletion and creation success, throwing an IOException if they fail.

```java
File tempDir = File.createTempFile("git", "");
if (!tempDir.delete()) {
    throw new IOException("Could not delete temp file: " + tempDir);
}
if (!tempDir.mkdirs()) {
    throw new IOException("Could not create temp directory: " + tempDir);
}
```

--------------------------------

### OpenRepository

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/03-porcelain-basic.md

Opens an existing Git repository using `FileRepositoryBuilder`.

```APIDOC
## OpenRepository

### Description
Opens an existing repository using `FileRepositoryBuilder`.

### Usage Pattern
```java
FileRepositoryBuilder builder = new FileRepositoryBuilder();
try (Repository repository = builder.setGitDir(new File(".git"))
        .readEnvironment()
        .build()) {
    // Use repository
}
```
```

--------------------------------

### Get Tree Object from Commit (Java)

Source: https://github.com/centic9/jgit-cookbook/blob/master/README.md

Retrieves the tree object associated with a commit. This is useful for accessing the file structure of a commit. Requires a Repository and a commit identifier.

```Java
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.treewalk.RevTree;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.storage.file.FileRepositoryBuilder;
import org.eclipse.jgit.revwalk.RevWalk;

import java.io.IOException;

public class GetRevTreeFromObjectId {

    public static void main(String[] args) throws IOException {
        try (Repository repository = new FileRepositoryBuilder()
                .setGitDir(new java.io.File(".git"))
                .readEnvironment()
                .findGitDir()
                .build()) {

            String commitIdString = "HEAD"; // or a SHA-1 string
            ObjectId commitId = repository.resolve(commitIdString);

            if (commitId != null) {
                try (RevWalk revWalk = new RevWalk(repository)) {
                    RevCommit commit = revWalk.parseCommit(commitId);
                    RevTree tree = commit.getTree();
                    System.out.println("Tree SHA-1: " + tree.getId().getName());
                }
            } else {
                System.out.println("Commit " + commitIdString + " not found.");
            }
        }
    }
}
```

--------------------------------

### Show Change Type for Files Between Commits

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/03-porcelain-basic.md

Extends the previous example to explicitly print the file name and its change type (added, modified, deleted, etc.) between two commits.

```java
for (DiffEntry diff : diffs) {
    System.out.println("File: " + diff.getNewPath());
    System.out.println("Change: " + diff.getChangeType());
}
```

--------------------------------

### Implement Simple Progress Monitor

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

A basic implementation of the ProgressMonitor interface for tracking task progress. Useful for providing user feedback during long-running operations.

```java
public class SimpleProgressMonitor implements ProgressMonitor {
    private int totalTasks;
    private String currentTask;
    
    @Override
    public void start(int totalTasks) {
        this.totalTasks = totalTasks;
    }
    
    @Override
    public void beginTask(String title, int totalWork) {
        this.currentTask = title;
        System.out.println("Starting: " + title);
    }
    
    @Override
    public void update(int completed) {
        System.out.print(".");
    }
    
    @Override
    public void endTask() {
        System.out.println("Done: " + currentTask);
    }
    
    @Override
    public boolean isCancelled() {
        return false;
    }
    
    @Override
    public void showDuration(boolean show) {
    }
}
```

--------------------------------

### Accessing Remote Repository Configuration

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/configuration.md

Shows how to read remote repository URLs, add new remotes using RemoteConfig, and list all configured remotes.

```java
// Read remote URL
String url = config.getString("remote", "origin", "url");

// Add remote
RemoteConfig remote = new RemoteConfig(config, "upstream");
remote.addURI(new URIish("https://github.com/upstream/repo.git"));
remote.update(config);
config.save();

// List all remotes
Set<String> remotes = config.getSubsections("remote");
for (String remoteName : remotes) {
    String remoteUrl = config.getString("remote", remoteName, "url");
    System.out.println(remoteName + " = " + remoteUrl);
}
```

--------------------------------

### Iterate Through a Tree's Contents

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/types.md

Use TreeWalk to recursively traverse a repository tree and access file paths and object IDs. Ensure the repository and tree are valid before starting.

```java
try (TreeWalk walk = new TreeWalk(repository)) {
    walk.addTree(tree);
    walk.setRecursive(true);
    
    while (walk.next()) {
        String path = walk.getPathString();
        ObjectId objectId = walk.getObjectId(0);
    }
}
```

--------------------------------

### Handling Repository Not Found Exception

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/errors.md

Illustrates wrapping an IOException in an IllegalStateException when a repository cannot be found.

```java
try {
    return CookbookHelper.openJGitCookbookRepository();
} catch (IOException e) {
    throw new IllegalStateException(
        "Could not find repository. Make sure you're in a git directory or " +
        "that $GIT_DIR is set.", e);
}
```

--------------------------------

### SimpleProgressMonitor Begin Task

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/api-reference/01-helpers.md

Begins a specific named task within the SimpleProgressMonitor. It prints the task title and total work units to standard output. Use this to delineate sub-operations.

```java
public void beginTask(String title, int totalWork)
```

--------------------------------

### Iterate Over Commits on a Branch (Java)

Source: https://github.com/centic9/jgit-cookbook/blob/master/README.md

Walks through all commits on a specified branch, starting from the branch's tip and going back in history. Requires a Repository object and a branch name.

```Java
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.storage.file.FileRepositoryBuilder;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.lib.ObjectId;

import java.io.IOException;

public class WalkRev {

    public static void main(String[] args) throws IOException {
        try (Repository repository = new FileRepositoryBuilder()
                .setGitDir(new java.io.File(".git"))
                .readEnvironment()
                .findGitDir()
                .build()) {

            String branchName = "refs/heads/master"; // or "master"
            ObjectId branchTip = repository.resolve(branchName);

            if (branchTip != null) {
                try (RevWalk revWalk = new RevWalk(repository)) {
                    RevCommit commit = revWalk.parseCommit(branchTip);
                    revWalk.markStart(commit);

                    System.out.println("Commits on branch '" + branchName + "':");
                    for (RevCommit rev : revWalk) {
                        System.out.println("- " + rev.getName() + ": " + rev.getShortMessage());
                    }
                }
            } else {
                System.out.println("Branch '" + branchName + "' not found.");
            }
        }
    }
}
```

--------------------------------

### Retrieve Working Directory and Index Status

Source: https://github.com/centic9/jgit-cookbook/blob/master/_autodocs/types.md

Use the Git.status() command to get a Status object representing the current state of the repository. Check if the repository is clean or if there are modified files.

```java
try (Git git = new Git(repository)) {
    Status status = git.status().call();
    
    if (!status.isClean()) {
        System.out.println("Changes: " + status.getModified());
    }
}
```

--------------------------------

### List All Tags in a Repository

Source: https://github.com/centic9/jgit-cookbook/blob/master/README.md

Fetches and displays all tags present in the Git repository. This is equivalent to 'git tag'.

```java
import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.api.ListTagCommand;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.lib.Ref;
import java.io.File;
import java.io.IOException;
import java.util.Collection;

public class ListTags {

    public static void main(String[] args) throws IOException, GitAPIException {
        File repoPath = new File("my_repo"); // Replace with your repository path

        try (Git git = Git.open(repoPath)) {
            ListTagCommand listTagCommand = git.tagList();
            Collection<Ref> tags = listTagCommand.call();

            System.out.println("Tags in the repository:");
            if (tags.isEmpty()) {
                System.out.println("No tags found.");
            } else {
                for (Ref tag : tags) {
                    System.out.println(tag.getName());
                }
            }
        }
    }
}
```