This class is derived from Attribute and represents a reference
to the source file of this class. At most one SourceFile attribute
should appear per classfile. The intention of this class is that it is
instantiated from the Attribute.readAttribute() method.
public SourceFile(int name_index,
name_index - Index in constant pool to CONSTANT_Utf8, which
should represent the string "SourceFile".
length - Content length in bytes, the value should be 2.
constant_pool - The constant pool that this attribute is
sourcefile_index - Index in constant pool to CONSTANT_Utf8. This
string will be interpreted as the name of the file from which this
class was compiled. It will not be interpreted as indicating the name
of the directory contqining the file or an absolute path; this
information has to be supplied the consumer of this attribute - in
many cases, the JVM.