OPAL is an extensible, Java bytecode processing, engineering, manipulation and analysis library written in Scala 2.12.x. OPAL supports Java 10 Bytecode and has preliminary support for Java 11; OPAL in particular provides support to facilitate the analysis of Java 8-10 lambda expressions (Invokedynamic instructions).

The latest release is 3.0.0, the latest snapshot version is 3.0.1-SNAPSHOT. Both versions are found on Maven central. If you want to use the snapshot version do not forget to add the respective resolver:

resolvers += "Sonatype OSS Snapshots" at "https://oss.sonatype.org/content/repositories/snapshots"

If you want to use OPAL for the development of static analyses, you can either use the latest release found on Maven Central or just checkout and build the current development snapshot of OPAL found one BitBucket. In general, using the development snapshot; i.e., the develop branch of OPAL is very safe and gives you access to the latest features, improvements and bug fixes.

Using The Latest Development Snapshot

Go to GitHub to checkout OPAL and to read how to compile and deploy it.

Using The Latest Release

The latest release is always found on Maven Central and can therefore be added to your project as standard library dependency.

OPAL consists of multiple sub projects and tools which are described in the following.


Contains general data structures and algorithms particular useful in the context of static analysis. E.g., graph algorithms, such as an implementation of Tarjan's algorithm for finding strongly connected components. The implementations are designed with scalability in mind and should be able to process millions of nodes.

libraryDependencies += "de.opal-project" % "common_2.12" % "3.0.0"

Static Analysis Framework

The static analysis framework is a generally useful framework for developing static analyses. The framework has wide ranging support for very different types of static analyses and automatically parallels their execution. The framework only depends on Common and can be flexibly combined with other static analyses frameworks (e.g., BCEL, SOOT, Wala, ASM,... )

libraryDependencies += "de.opal-project" % "static-analysis-infrastructure_2.12" % "3.0.0"

Bytecode Representation

The bytecode toolkit implements a generic infrastructure for parsing Java class files. Additionally, it provides a default representation for Java bytecode that can be used to analyze class files. That representation provides extensive support for pattern matching on Java bytecode to facilitate writing basic analyses.

libraryDependencies += "de.opal-project" % "bytecode-representation_2.12" % "3.0.0"

Architecture Validation Framework

The architecture validation framework facilitates the development of tools for specifying and validating software architectures.

libraryDependencies += "de.opal-project" % "architecture-validation_2.12" % "3.0.0"

Abstract Interpretation Framework

The abstract interpretation framework is a highly-customizable framework for the lightweight abstract interpretation of the Java bytecode. The framework was designed with ease of use and customizability in mind.

libraryDependencies += "de.opal-project" % "abstract-interpretation-framework_2.12" % "3.0.0"

OPAL based Tools

OPAL Java Bytecode Disassembler

Disassembles your Java bytecode.

Using OPAL

OPAL comes with a huge number of code snippets and small (i.e., one-class) analyses to demonstrate various features.