• Requires Java 6+.
• Uses Redmine's REST API (don't forget to enable it in the Redmine server settings).
• Does not require any plugins installed on Redmine/Chiliproject server.
• Runs on any standard Java platform
• Supports HTTP proxy
• Supports GZipped responses from servers
• Uses SLF4J for logging. Provide your own SLF4J binding
• [Supported Redmine versions] (https://github.com/taskadapter/redmine-java-api/wiki/Redmine-versions-compatibility)
• Available in Maven Central.

Gradle dependency:

dependencies {
    compile 'com.taskadapter:redmine-java-api:2.1.0'
}

Check the latest release version in Maven Central

Sample code to retrieve list of Redmine issues:

private static String uri = "https://www.hostedredmine.com";
private static String apiAccessKey = "a3221bfcef5750219bd0a2df69519416dba17fc9";
private static String projectKey = "taskconnector-test";
private static Integer queryId = null; // any

RedmineManager mgr = RedmineManagerFactory.createWithApiKey(uri, apiAccessKey);
List<Issue> issues = mgr.getIssueManager().getIssues(projectKey, queryId);
for (Issue issue : issues) {
    System.out.println(issue.toString());
}

• Install Gradle 2.1+.
• To build in command line: run "gradle build".
• To open the project code in IDEA or Eclipse: open "build.gradle" file. Your IDE will create a project basing on the gradle's script.
• Please make sure you add unit and/or integration tests when submitting your changes. Don't forget to document the required Redmine version and other limitations.