# Class Code

java.lang.Object
org.apache.bcel.classfile.Attribute
org.apache.bcel.classfile.Code

All Implemented Interfaces:
  `Cloneable, Node`

public final class Code extends Attribute
This class represents a chunk of Java byte code contained in a method. It is instantiated by the Attribute.readAttribute() method. A Code attribute contains informations about operand stack, local variables, byte code and the exceptions handled within this method. This attribute has attributes itself, namely LineNumberTable which is used for debugging purposes and LocalVariableTable which contains information about the local variables.

    Code_attribute {
      u2 attribute_name_index;
      u4 attribute_length;
      u2 max_stack;
      u2 max_locals;
      u4 code_length;
      u1 code[code_length];
      u2 exception_table_length;
      {
        u2 start_pc;
        u2 end_pc;
        u2 handler_pc;
        u2 catch_type;
      } exception_table[exception_table_length];
      u2 attributes_count;
      attribute_info attributes[attributes_count];
    }

See Also:
  - `Attribute`
  - `CodeException`
  - `LineNumberTable`
  - `LocalVariableTable`

- ## Field Summary

  ### Fields inherited from class Attribute

  `constant_pool, EMPTY_ARRAY, length, name_index, tag`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `Code(int nameIndex, int length, int maxStack, int maxLocals, byte[] code, CodeException[] exceptionTable, Attribute[] attributes, ConstantPool constantPool)`
  `Code(Code code)`
  Initialize from another object.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `accept(Visitor v)`
  Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
  `Attribute`
  `copy(ConstantPool constantPool)`
  `void`
  `dump(DataOutputStream file)`
  Dump code attribute to file stream in binary format.
  `Attribute[]`
  `getAttributes()`
  `byte[]`
  `getCode()`
  `CodeException[]`
  `getExceptionTable()`
  `LineNumberTable`
  `getLineNumberTable()`
  `LocalVariableTable`
  `getLocalVariableTable()`
  `LocalVariableTypeTable`
  `getLocalVariableTypeTable()`
  Gets the local variable type table attribute `LocalVariableTypeTable`.
  `int`
  `getMaxLocals()`
  `int`
  `getMaxStack()`
  `StackMap`
  `getStackMap()`
  Finds the attribute of `StackMap` instance.
  `void`
  `setAttributes(Attribute[] attributes)`
  `void`
  `setCode(byte[] code)`
  `void`
  `setExceptionTable(CodeException[] exceptionTable)`
  `void`
  `setMaxLocals(int maxLocals)`
  `void`
  `setMaxStack(int maxStack)`
  `String`
  `toString()`
  `String`
  `toString(boolean verbose)`
  Converts this object to a String.

  ### Methods inherited from class Attribute

  `addAttributeReader, addAttributeReader, clone, getConstantPool, getLength, getName, getNameIndex, getTag, println, readAttribute, readAttribute, removeAttributeReader, setConstantPool, setLength, setNameIndex`

  ### Methods inherited from class Object

  `equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- ## Constructor Details

  - ### Code

    public Code(Code code)
    Initialize from another object. Note that both objects use the same references (shallow copy). Use copy() for a physical copy.
    Parameters:
      `code` - The source Code.

  - ### Code

    public Code(int nameIndex, int length, int maxStack, int maxLocals, byte[] code, CodeException[] exceptionTable, Attribute[] attributes, ConstantPool constantPool)
    Parameters:
      `nameIndex` - Index pointing to the name Code
      `length` - Content length in bytes
      `maxStack` - Maximum size of stack
      `maxLocals` - Number of local variables
      `code` - Actual byte code
      `exceptionTable` - of handled exceptions
      `attributes` - Attributes of code: LineNumber or LocalVariable
      `constantPool` - Array of constants

- ## Method Details

  - ### accept

    public void accept(Visitor v)
    Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class. I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
    Specified by:
      `accept` in interface `Node`
    Specified by:
      `accept` in class `Attribute`
    Parameters:
      `v` - Visitor object

  - ### copy

    public Attribute copy(ConstantPool constantPool)
    Specified by:
      `copy` in class `Attribute`
    Parameters:
      `constantPool` - the constant pool to duplicate
    Returns:
      deep copy of this attribute

  - ### dump

    public void dump(DataOutputStream file) throws IOException
    Dump code attribute to file stream in binary format.
    Overrides:
      `dump` in class `Attribute`
    Parameters:
      `file` - Output file stream
    Throws:
      `IOException` - if an I/O error occurs.

  - ### getAttributes

    public Attribute[] getAttributes()
    Returns:
      Collection of code attributes.
    See Also:
      - `Attribute`

  - ### getCode

    public byte[] getCode()
    Returns:
      Actual byte code of the method.

  - ### getExceptionTable

    public CodeException[] getExceptionTable()
    Returns:
      Table of handled exceptions.
    See Also:
      - `CodeException`

  - ### getLineNumberTable

    public LineNumberTable getLineNumberTable()
    Returns:
      LineNumberTable of Code, if it has one

  - ### getLocalVariableTable

    public LocalVariableTable getLocalVariableTable()
    Returns:
      LocalVariableTable of Code, if it has one

  - ### getLocalVariableTypeTable

    public LocalVariableTypeTable getLocalVariableTypeTable()
    Gets the local variable type table attribute `LocalVariableTypeTable`.
    Returns:
      LocalVariableTypeTable of Code, if it has one, null otherwise.
    Since:
      6.10.0

  - ### getMaxLocals

    public int getMaxLocals()
    Returns:
      Number of local variables.

  - ### getMaxStack

    public int getMaxStack()
    Returns:
      Maximum size of stack used by this method.

  - ### getStackMap

    public StackMap getStackMap()
    Finds the attribute of `StackMap` instance.
    Returns:
      StackMap of Code, if it has one, else null.
    Since:
      6.8.0

  - ### setAttributes

    public void setAttributes(Attribute[] attributes)
    Parameters:
      `attributes` - the attributes to set for this Code

  - ### setCode

    public void setCode(byte[] code)
    Parameters:
      `code` - byte code

  - ### setExceptionTable

    public void setExceptionTable(CodeException[] exceptionTable)
    Parameters:
      `exceptionTable` - exception table

  - ### setMaxLocals

    public void setMaxLocals(int maxLocals)
    Parameters:
      `maxLocals` - maximum number of local variables

  - ### setMaxStack

    public void setMaxStack(int maxStack)
    Parameters:
      `maxStack` - maximum stack size

  - ### toString

    public String toString()
    Overrides:
      `toString` in class `Attribute`
    Returns:
      String representation of code chunk.

  - ### toString

    public String toString(boolean verbose)
    Converts this object to a String.
    Parameters:
      `verbose` - Provides verbose output when true.
    Returns:
      String representation of code chunk.