joernio / javasrc2cpg   0.0.18

Apache License 2.0 GitHub

Java source code frontend

Scala versions: 2.13


This is a CPG frontend based on Java source code powered by JavaParser.

release Discord




  1. Clone the project
  2. Build the project sbt stage
  3. Create a CPG ./ /path/to/your/code -o /path/to/cpg.bin
  4. Download Joern with
    cd joern-cli
  5. Copy cpg.bin into the Joern directory
  6. Start Joern with ./
  7. Import the cpg with importCpg("cpg.bin")
  8. Now you can query the CPG


Some general development habits for the project:

  • When making a branch, use the following template <short-name>/<feature-or-bug-name> e.g. fabs/control-structure-nodes.
  • We currently focus around test driven development. Pay attention to the code coverage when creating new tests and features. The code coverage report can be found under ./target/scala-2.13/scoverage-report.


  • Explicit constructor invocations
  • Propagate context up and down while creating AST
  • code field for method calls (this for System.out in System.out.println)
  • Logging
  • Handle body of try/catch
  • Local class declaration statements
  • Lambda expressions
  • Method Reference Expr
  • Throw statements (AST is simple, control flow to catch seems harder)
  • this/super expressions (scope for FieldAccess)
  • Type expressions (part of MethodReferenceExpr)
  • instanceof
  • Pattern expr as part of instanceof (Java 14)
  • switch expressions (including yield statements) (Introduced Java 12/13)
  • Local record declaration statements (Java 14 Preview feature)
  • Dataflow tests for inheritance


  • Type arguments for generics
  • Annotations
  • Cast expressions (maybe not necessary if javaparser resolves types correctly)
  • Synchronized statements (if we don't just ignore those)
  • Control flow for labeled breaks