Use the Eclipse Java Development Tools in a Java SE application

<project xmlns="http://maven.apache.org/POM/4.0.0"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>example</groupId>
  <artifactId>java-formatter</artifactId>
  <version>1.0.0-SNAPSHOT</version>

  <dependencies>
    <dependency>
      <groupId>org.eclipse.jdt</groupId>
      <artifactId>org.eclipse.jdt.core</artifactId>
      <version>3.12.2</version>
    </dependency>
  </dependencies>
</project>

import java.util.Properties;

import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jdt.core.ToolFactory;
import org.eclipse.jdt.core.formatter.CodeFormatter;
import org.eclipse.jdt.internal.compiler.impl.CompilerOptions;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.Document;
import org.eclipse.jface.text.IDocument;
import org.eclipse.text.edits.TextEdit;

public class MainFormatter {

  public static void main(String[] args) {
    String result;

    String javaCode = "public class MyClass{ "
                        + "public static void main(String[] args) { "
                        + "System.out.println(\"Hello World\");"
                        + " }"
                        + " }";

    Properties prefs = new Properties();
    prefs.setProperty(JavaCore.COMPILER_SOURCE, CompilerOptions.VERSION_1_8);
    prefs.setProperty(JavaCore.COMPILER_COMPLIANCE, CompilerOptions.VERSION_1_8);
    prefs.setProperty(JavaCore.COMPILER_CODEGEN_TARGET_PLATFORM, CompilerOptions.VERSION_1_8);

    CodeFormatter codeFormatter = ToolFactory.createCodeFormatter(prefs);
    IDocument doc = new Document(javaCode);
    try {
      TextEdit edit = codeFormatter.format(CodeFormatter.K_COMPILATION_UNIT | CodeFormatter.F_INCLUDE_COMMENTS,
                                             javaCode, 0, javaCode.length(), 0, null);
      if (edit != null) {
        edit.apply(doc);
        result = doc.get();
      }
      else {
        result = javaCode;
      }
    }
    catch (BadLocationException e) {
      throw new RuntimeException(e);
    }

    System.out.println(result);
  }
}