• package root
    Definition Classes
  • package org
    Definition Classes
  • package opalj

    OPAL is a Scala-based framework for the static analysis, manipulation and creation of Java bytecode.

    OPAL is a Scala-based framework for the static analysis, manipulation and creation of Java bytecode. OPAL is designed with performance, scalability and adaptability in mind.

    Its main components are:

    • a library (Common) which provides generally useful data-structures and algorithms for static analyses.
    • a framework for implementing lattice based static analyses (Static Analysis Infrastructure)
    • a framework for parsing Java bytecode (Bytecode Infrastructure) that can be used to create arbitrary representations.
    • a library to create a one-to-one in-memory representation of Java bytecode (Bytecode Disassembler).
    • a library to create a representation of Java bytecode that facilitates writing simple static analyses (Bytecode Representation -
    • a scalable, easily customizable framework for the abstract interpretation of Java bytecode (Abstract Interpretation Framework -
    • a library to extract dependencies between code elements and to facilitate checking architecture definitions.
    • a library for the lightweight manipulation and creation of Java bytecode (Bytecode Assembler).

    General Design Decisions

    Thread Safety

    Unless explicitly noted, OPAL is thread safe. I.e., the classes defined by OPAL can be considered to be thread safe unless otherwise stated. (For example, it is possible to read and process class files concurrently without explicit synchronization on the client side.)

    No null Values

    Unless explicitly noted, OPAL does not null values I.e., fields that are accessible will never contain null values and methods will never return null. If a method accepts null as a value for a parameter or returns a null value it is always explicitly documented. In general, the behavior of methods that are passed null values is undefined unless explicitly documented.

    No Typecasts for Collections

    For efficiency reasons, OPAL sometimes uses mutable data-structures internally. After construction time, these data-structures are generally represented using their generic interfaces (e.g., scala.collection.{Set,Map}). However, a downcast (e.g., to add/remove elements) is always forbidden as it would effectively prevent thread-safety.


    OPAL makes heavy use of Scala's Assertion Facility to facilitate writing correct code. Hence, for production builds (after thorough testing(!)) it is highly recommend to build OPAL again using -Xdisable-assertions.

    Definition Classes
  • package ai

    Implementation of an abstract interpretation (ai) framework – also referred to as OPAL.

    Implementation of an abstract interpretation (ai) framework – also referred to as OPAL.

    Please note that OPAL/the abstract interpreter just refers to the classes and traits defined in this package (ai). The classes and traits defined in the sub-packages (in particular in domain) are not considered to be part of the core of OPAL/the abstract interpreter.

    Definition Classes

    This framework assumes that the analyzed bytecode is valid; i.e., the JVM's bytecode verifier would be able to verify the code. Furthermore, load-time errors (e.g., LinkageErrors) are – by default – completely ignored to facilitate the analysis of parts of a project. In general, if the presented bytecode is not valid, the result is undefined (i.e., OPAL may report meaningless results, crash or run indefinitely).

    See also - Implements the abstract interpreter that processes a methods code and uses an analysis-specific domain to perform the abstract computations. - The core interface between the abstract interpretation framework and the abstract domain that is responsible for performing the abstract computations.

  • package domain

    This package contains definitions of common domains that can be used for the implementation of analyses.

    This package contains definitions of common domains that can be used for the implementation of analyses.

    Types of Domains

    In general, we distinguish two types of domains. First, domains that define a general interface (on top of the one defined by Domain), but do not directly provide an implementation. Hence, whenever you develop a new Domain you should consider implementing/using these domains to maximize reusability. Second, Domains that implement a specific interface (trait). In this case, we further distinguish between domains that provide a default implementation (per interface only one of these Domains can be used to create a final Domain) and those that can be stacked and basically refine the overall functionality.


    • Domains That Define a General Interface
      • Origin defines two types which domains that provide information abou the origin of a value should consider to implement.
      • TheProject defines a standard mechanism how a domain can access the current project.
      • ...
    • Domains That Provide a Default Implementation
    • Domains That Implement Stackable Functionality
      • records information about all uncaught exceptions by intercepting a Domain's respective methods. However, it does provide a default implementation. Hence, a typical pattern is:
    class MyDomain extends Domain with ...
        with DefaultHandlingOfMethodResults with RecordThrownExceptions

    Thread Safety

    Unless explicitly documented, a domain is never thread-safe. The general programming model is to use one Domain object per code block/method and therefore, thread-safety is not required for Domains that are used for the evaluation of methods. However domains that are used to adapt/transfer values should be thread safe (see for further details).

    Definition Classes
  • package l0
    Definition Classes
  • package l1

    Commonly useful methods.

    Commonly useful methods.

    Definition Classes
  • package l2
    Definition Classes
  • CalledMethodsStore
  • ChildDefaultDomain
  • ChildPerformInvocationsWithRecursionDetection
  • CoordinatingValuesDomain
  • DefaultDomain
  • DefaultPerformInvocationsDomain
  • DefaultPerformInvocationsDomainWithCFG
  • DefaultPerformInvocationsDomainWithCFGAndDefUse
  • PerformInvocations
  • PerformInvocationsWithRecursionDetection
  • SharedDefaultDomain
  • SharedValuesDomain
  • package tracing
    Definition Classes

package l2

  1. Alphabetic
  1. Public
  2. Protected

Type Members

  1. trait CalledMethodsStore extends AnyRef

    Stores information about how methods were called.

    Stores information about how methods were called.

    Thread Safety

    "CalledMethodsStore" are immutable.

  2. class ChildDefaultDomain[Source] extends SharedDefaultDomain[Source] with ChildPerformInvocationsWithRecursionDetection with DefaultRecordMethodCallResults
  3. trait ChildPerformInvocationsWithRecursionDetection extends PerformInvocationsWithRecursionDetection
  4. class CoordinatingValuesDomain[Source] extends ValuesCoordinatingDomain with SharedValuesDomain[Source]

    A basic Domain that is used to identify recursive calls.

  5. class DefaultDomain[Source] extends SharedDefaultDomain[Source] with PerformInvocationsWithRecursionDetection with RecordCFG with TheMemoryLayout
  6. class DefaultPerformInvocationsDomain[Source] extends SharedDefaultDomain[Source] with PerformInvocations

    Performs a simple invocation of the immediately called methods.

  7. class DefaultPerformInvocationsDomainWithCFG[Source] extends DefaultPerformInvocationsDomain[Source] with RecordCFG
  8. class DefaultPerformInvocationsDomainWithCFGAndDefUse[Source] extends DefaultPerformInvocationsDomainWithCFG[Source] with RefineDefUseUsingOrigins
  9. trait PerformInvocations extends MethodCallsHandling

    Mix in this trait if methods that are called by invokeXYZ instructions should actually be interpreted using a custom domain.

  10. trait PerformInvocationsWithRecursionDetection extends PerformInvocations with TheMemoryLayout

    Enables to perform invocations.

    Enables to perform invocations.


    (PerformInvocationsWithRecursionDetection is in particular used by BugPicker's domain.)

  11. class SharedDefaultDomain[Source] extends TheMethod with ThrowAllPotentialExceptionsConfiguration with DefaultHandlingOfMethodResults with IgnoreSynchronization with TypeLevelFieldAccessInstructions with TypeLevelInvokeInstructions with TypeLevelDynamicLoads with SpecialMethodsHandling with SharedValuesDomain[Source] with MaxArrayLengthRefinement with NullPropertyRefinement with LongValuesShiftOperators with ConcretePrimitiveValuesConversions

    Domain that uses the l1 and l2 level stable domains.

    Domain that uses the l1 and l2 level stable domains.


    This domain is intended to be used for demo purposes only. Tests should create their own domains to make sure that the test results remain stable. The configuration of this domain just reflects a reasonable configuration that may change without further notice.

  12. trait SharedValuesDomain[Source] extends CorrelationalDomain with DefaultSpecialDomainValuesBinding with TheProject with DefaultTypeLevelFloatValues with DefaultTypeLevelDoubleValues with TypeLevelDynamicLoads with DefaultClassValuesBinding with DefaultArrayValuesBinding with DefaultIntegerRangeValues with DefaultLongValues

    A domain that defines a common reference frame for all subsequent domains.

Value Members

  1. object CalledMethodsStore