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Sequence Diagram is tool to generate simple sequence diagram(UML) from java, kotlin, scala(Beta) and groovy(limited) code.

with this plugin, you can

Experimental features

The experimental features created by myself, which is not part of UML standard. Use this feature in your own risk.

UAST support (since version 3.x)

SequenceDiagram version 3.x will use UAST api to generate sequence diagram.

Refer to ‘The UAST description from IntelliJ Platform SDK’

UAST (Unified Abstract Syntax Tree) is an abstraction layer on the PSI of different programming languages targeting the JVM (Java Virtual Machine). It provides a unified API for working with common language elements like classes and method declarations, literal values, and control flow operators.

Which languages are supported?

There are some limitation when generate from scala or groovy code. Refer to the list of known issues.

Smart Interface

Find the implementation of the interface smartly. e.g.

public interface Fruit {
    int eat();

public class Apple implements Fruit {
    public int eat() {
        return 5;

Apple implemented the Fruit interface. When we generate sequence diagram for the eatFruit method:

public class People {
    private Fruit fruit = new Apple();

    public void eatFruit() {;

I draw dummy implementation call in dash line.

Smart Interface

For the interface or abstract class, if there is only one implementation found, it will draw in diagram automatically. More than one implementation, you need to choose one to draw. this is an option in settings.

Lambda Expression

No standard for the lambda expression in the sequence diagram yet. So I create mine. e.g.

public interface Service<Int, String> {

    String invoke(Int a);

I need draw the sequence diagram for hello method:

public class Lambda {

    public Service<Integer, String> hello() {
        return a -> {
            Fruit fruit = new Apple();
            return "I'm good!";

I draw a dummy () -> self call in diagram.

Lambda Expression

How to use

Sequence Diagram can generate sequence diagram from JAVA, Kotlin, Scala, Groovy File.

  1. Open Java/Kotlin/Scala/Groovy file
  2. Generate SequenceDiagram with shortcut Alt S for windows, Option S for macOS

Please try to experience it and find what happen.

Have fun!

Version History

Current Version

JetBrains Plugins

Version and API comparison

Open API v2.x.x v3.x
IGenerator SequenceGenerator
GeneratorFactory JavaGeneratorFactory
ElementTypeFinder JavaElementTypeFinder
ActionFinder JavaActionFinder
SequenceNavigable JavaSequenceNavigable

Function comparison

  v2.x.x 3.x
Kotlin ✓ Partial
Groovy   ✓ Partial
Navigation Bar  
Tools Menu
Editor Context Menu
Shortcut Alt S for windows
Option S for macOS
Project view popup menu    
Structure view popup menu    
Smart Interface2 ✓ EXC: 2.2.4, 2.2.5
Smart Interface configuration  
Lambda call configuration

versions history:


Known issue

1. Scala for comprehension calls is not supported

For example:

class B() {
  def bar() = Option("bar")

class A(b: B) {
  def foo() = {
    val r = "foo" +"?")

  def foo2() = {
    val r = for {
      x <-
    } yield "foo" + x

the for comprehension call

val r = for {
      x <-
    } yield "foo" + x

it’s UAST tree is UastEmptyexpression.

 UMethod (name = foo2)
                    ULocalVariable (name = r)
                        UastEmptyExpression(type = PsiType:Option<String>)
                        USimpleNameReferenceExpression (identifier = r)
                        UMethodCall(name = getOrElse)
                            UIdentifier (Identifier (getOrElse))
                            ULiteralExpression (value = "?")

so the method call will not generate base on UastEmptyexpression. Hopefully, the UAST api will solve this problem sooner.

2. Groovy method body is not supported

For example:

 * A Class description
class Student {
    /** the name of the person */
    String name

     * Creates a greeting method for a certain person.
     * @param otherPerson the person to greet
     * @return a greeting message
    //known issue: groovy method will not generate in UAST
    String greet(String otherPerson) {
        "Hello ${otherPerson}"
        // call java
        Fruit fruit = new Banana()


Based on UAST api limitation, it’s UAST tree is no method body mappings.

UFile (package = van.demo.grovvy)
    UClass (name = Student)
        UMethod (name = greet)
            UParameter (name = otherPerson)

When generate sequence of method greet, the calls in the method body will not generate (the call java code in the body of greet).

        "Hello ${otherPerson}"
        // call java
        Fruit fruit = new Banana()


Name history

Why change name?

Since 2011, I found a solution of NPE of original SequencePlugin, so I write email to Kentaur with my solution, He said he was not coding anymore. Instead, he sent me the code. I fix the NPE issue and publish to plugin repository with new name SequencePluginReload.

In 2015, the IntelliJ change the login system, and I lost my account, cannot continue to publish new version to the repository.

In 2016, I change the Name again to SequenceDiagram and host the source code on github. Now it is open source.

Thanks Kentaur for the great work on the original source.

  1. JavaSequenceNavigable work for Java, Kotlin, Scala, Groovy 

  2. Smart interface will scan entire file and spend more generate time.