Practical Information

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Go here and fill the form.

How to access Spoon's source code repository?


What is the meaning of each digit in the version X.Y.Z of spoon?

  • X is the digit for the major version (major new features or major incompatible API changes).
  • Y is the digit for the minor version (bug fixes or minor API changes).
  • Z is the digit for the critical bug fixes of the current major or minor version.


Where is the Spoon metamodel?

The Spoon metamodel consists of all interfaces that are in packages spoon.reflect.declaration (structural part: classes, methods, etc.) and spoon.reflect.code (behavioral part: if, loops, etc.).

How to get a Spoon model programmatically?

Launcher spoon = new Launcher();
Factory factory = spoon.getFactory();
// list all packages of the model
for(CtPackage p : factory.Package().getAll()) {
  System.out.println("package: "+p.getQualifiedName());
// list all classes of the model
for(CtType<?> s : factory.Class().getAll()) {
  System.out.println("class: "+s.getQualifiedName());


How to prevent Annotation processors from consuming the annotations that they process?

By default, whenever an Annotation Processor processes a CtElement it will consume (delete) the processed annotation from it. If you want the annotation to be kept, override the init() method from the AbstractAnnotationProcessor class, and call the protected method clearConsumedAnnotationTypes like so:

public void init() {

How to compare and create type references in a type-safe way?

Use actual classes instead of strings.

CtTypeReference t=...
if(t.getActualClass()==int.class) { ... }
Factory f=...

How to parametrized the JDT compiler arguments?

SpoonModelBuilder exposes a method named build(JDTBuilder). This method compiles the target source code with data specified in the JDTBuilder parameter.

final String[] builder = new JDTBuilderImpl() //
        .classpathOptions(new ClasspathOptions().classpath(TEST_CLASSPATH).bootclasspath(TEST_CLASSPATH).binaries(".").encoding("UTF-8")) //
        .complianceOptions(new ComplianceOptions().compliance(8)) //
        .annotationProcessingOptions(new AnnotationProcessingOptions().compileProcessors()) //
        .advancedOptions(new AdvancedOptions().continueExecution().enableJavadoc().preserveUnusedVars()) //
        .sources(new SourceOptions().sources(".")) //

How to use Spoon as an alternative reflection API?

Use TypeFactory as follows.

CtType s = new TypeFactory().get(String.class);

## What are references? How are they handled?

Spoon analyzes source code. However, this source code may refer to libraries (as a field, parameter, or method return type). Those library may be or not in the classpath. The boundary between source and libraries is handled by the reference mechanism.

When you're consider a reference object (say, a TypeReference), there are three cases:

- Case 1: the reference points to a code element for which the source code is present. In this case, reference.getDeclaration() returns this code element (e.g. TypeReference.getDeclaration returns the CtType representing the given java file). reference.getTypeDeclaration() is identical to reference.getDeclaration().
- Case 2: the reference points to a code element for which the source code is NOT present, but for which the binary class is in the classpath (either the JVM classpath or the --source-classpath argument). In this case, reference.getDeclaration() returns null and reference.getTypeDeclaration returns a partial CtType built using runtime reflection. Those objects built using runtime reflection are called shadow objects; and you can identify them with method isShadow. (This also holds for getFieldDeclaration and getExecutableDeclaration)
- Case 3: : the reference points to a code element for which the source code is NOT present, but for which the binary class is NOT in the classpath. This is called in Spoon the noclasspath mode. In this case, both reference.getDeclaration() and reference.getTypeDeclaration() return null. (This also holds for getFieldDeclaration and getExecutableDeclaration)