Interface JavaClass

All Known Implementing Classes:
DTFJJavaClass, JavaAbstractClass, JavaArrayClass, JavaClass, JCJavaClass
public interface JavaClass
Represents a Java class.

  • Field Details

    • MODIFIERS_UNAVAILABLE

      static final int MODIFIERS_UNAVAILABLE
      MODIFIERS_UNAVAILABLE is returned by getModifiers() when the modifiers are unavailable. The value 0xff000000 is chosen as it is a value that can never return true to any of the java.reflect.Modifier methods that test the modifier: isNative(), isPublic(), etc. while at the same time not being 0 which is a possible value when no modifier at all is present i.e. "default". All other values for the modifier returned are defined in java.lang.reflect.Modifiers
      See Also:

  • Method Details

    • getObject

      JavaObject getObject() throws CorruptDataException
      Fetch the java.lang.Class object associated with this class.

      In some implementations this may be null if no object has been created to represent this class, or if the class is synthetic.

      Returns:
      the java.lang.Class object associated with this class
      Throws:
      CorruptDataException
      See Also:

    • getClassLoader

      JavaClassLoader getClassLoader() throws CorruptDataException
      Fetch the class loader associated with this class. Classes defined in the bootstrap class loader (including classes representing primitive types or void) will always return a JavaClassLoader representing the bootstrap class loader. This asymmetry with java.lang.Class#getClassLoader() is intentional.
      Returns:
      the JavaClassLoader in which this class was defined
      Throws:
      CorruptDataException - if the class loader for this class cannot be found (a class cannot exist without a loader so this implies corruption)

    • getName

      String getName() throws CorruptDataException
      Get the name of the class.
      Returns:
      the name of the class in the form: "full/package/class$innerclass"
      Throws:
      CorruptDataException

    • getSuperclass

      JavaClass getSuperclass() throws CorruptDataException
      Get the immediate superclass of this class.
      Returns:
      the immediate superclass of this class, or null if this class has no superclass. For interfaces, Object, primitive types and void null is always returned.
      Throws:
      CorruptDataException

    • getInterfaces

      Iterator getInterfaces()
      Get the set of names of interfaces directly implemented by this class.
      Returns:
      an iterator over the collection of the names of interfaces directly implemented by this class. Some JVM implementations may choose to load interfaces lazily, so only the names are returned. The JavaClass objects may be found through the defining class loader.
      See Also:

    • getModifiers

      int getModifiers() throws CorruptDataException
      Return the Java language modifiers for this class.

      The modifiers are defined by the JVM Specification.

      Return MODIFIERS_UNAVAILABLE if the modifiers are unavailable. This might be the case if DTFJ is operating against an artefact such as a portable heap dump that does not contain information about a class's modifiers.

      Note that, for inner classes, the actual modifiers are returned, not the synthetic modifiers. For instance, a class will never have its 'protected' modifier set, even if the inner class was a protected member, since 'protected' is not a legal modifier for a class file.

      Returns:
      the modifiers for this class
      Throws:
      CorruptDataException

    • isArray

      boolean isArray() throws CorruptDataException
      Is this an array class ?
      Returns:
      true if this class is an array class
      Throws:
      CorruptDataException

    • getComponentType

      JavaClass getComponentType() throws CorruptDataException
      For array classes, returns a JavaClass representing the component type of this array class.
      Returns:
      a JavaClass representing the component type of this array class
      Throws:
      CorruptDataException
      IllegalArgumentException - if this JavaClass does not represent an array class

    • getDeclaredFields

      Iterator getDeclaredFields()
      Get the set of fields declared in this class.
      Returns:
      an iterator over the collection of fields declared in this class.
      See Also:

    • getDeclaredMethods

      Iterator getDeclaredMethods()
      Get the set of methods declared in this class.
      Returns:
      an iterator over the collection of methods declared in this class.
      See Also:

    • getConstantPoolReferences

      Iterator getConstantPoolReferences()
      Java classes may refer to other classes and to String objects via the class's constant pool. These references are followed by the garbage collector, forming edges on the graph of reachable objects. This getConstantPoolReferences() may be used to determine which objects are referred to by the receiver's constant pool.

      Although Java VMs typically permit only Class and String objects in the constant pool, some esoteric or future virtual machines may permit other types of objects to occur in the constant pool. This API imposes no restrictions on the types of JavaObjects which might be included in the Iterator.

      No assumption should be made about the order in which constant pool references are returned.

      Classes may also refer to objects through static variables. These may be found with the getDeclaredFields() API. Objects referenced by static variables are not returned by getConstantPoolReferences() unless the object is also referenced by the constant pool.

      Returns:
      an iterator over the collection of JavaObjects which are referred to by the constant pool of this class
      See Also:

    • getID

      ImagePointer getID()
      The ID of a class is a pointer to a section of memory which identifies the class. The contents of this memory are implementation defined.

      In some implementations getID() and getObject().getID() may return the same value. This implies that the class object is also the primary internal representation of the class. DTFJ users should not rely on this behaviour.

      In some implementations, getID() may return null for some classes. This indicates that the class is a synthetic class which has been constructed for DTFJ purposes only. The class has no physical representation in the VM.

      Returns:
      a pointer to the class

    • getReferences

      Iterator getReferences()
      Get the set of references from this class.
      Returns:
      an iterator of JavaReferences
      See Also:

    • equals

      boolean equals(Object obj)
      Description copied from class: java.lang.Object
      Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison. The implementation in Object answers true only if the argument is the exact same object as the receiver (==).
      Overrides:
      equals in class Object
      Parameters:
      obj -
      Returns:
      True if the given object refers to the same Java Class in the image
      See Also:

    • getInstanceSize

      long getInstanceSize() throws DataUnavailable, CorruptDataException
      Returns the size in bytes of an instance of this class on the heap.

      The call is only meaningful for a non-array JavaClass, where all instances of the class are of the same size. If this method is called on a JavaArrayClass, where instances can be of different sizes, an UnsupportedOperationException will be thrown. DataUnavailable can be thrown if no value is available: for example when DTFJ is examining a javacore, where the instance size for a class is not recorded.

      Returns:
      size in bytes of an instance
      Throws:
      DataUnavailable
      CorruptDataException
      UnsupportedOperationException - if the JavaClass is an instance of JavaArrayClass
      Since:
      1.6

    • hashCode

      int hashCode()
      Description copied from class: java.lang.Object
      Answers an integer hash code for the receiver. Any two objects which answer true when passed to .equals must answer the same value for this method.
      Overrides:
      hashCode in class Object
      Returns:
      the receiver's hash.
      See Also:

    • getProtectionDomain

      JavaObject getProtectionDomain() throws DataUnavailable, CorruptDataException
      Returns the protection domain for this class.
      Returns:
      the protection domain or null for the default protection domain
      Throws:
      DataUnavailable
      CorruptDataException
      Since:
      9