public  void close() throws IOException
Releases any resources opened by this file manager directly or
indirectly.  This might render this file manager useless and
the effect of subsequent calls to methods on this object or any
objects obtained through this object is undefined unless
explicitly allowed.  However, closing a file manager which has
already been closed has no effect.

 public  void flush() throws IOException
Flushes any resources opened for output by this file manager
directly or indirectly.  Flushing a closed file manager has no
effect.

 public ClassLoader getClassLoader(Location location)
Gets a class loader for loading plug-ins from the given
location.  For example, to load annotation processors, a
compiler will request a class loader for the 
ANNOTATION_PROCESSOR_PATH  location.

 public FileObject getFileForInput(Location location,
    String packageName,
    String relativeName) throws IOException
Gets a {@linkplain FileObject file object} for input
representing the specified relative
name in the specified package in the given location.

If the returned object represents a {@linkplain
JavaFileObject.Kind#SOURCE source} or {@linkplain
JavaFileObject.Kind#CLASS class} file, it must be an instance
of JavaFileObject .

Informally, the file object returned by this method is
located in the concatenation of the location, package name, and
relative name.  For example, to locate the properties file
"resources/compiler.properties" in the package
"com.sun.tools.javac" in the {@linkplain
StandardLocation#SOURCE_PATH SOURCE_PATH} location, this method
might be called like so:

getFileForInput(SOURCE_PATH, "com.sun.tools.javac", "resources/compiler.properties");

If the call was executed on Windows, with SOURCE_PATH set to
"C:\Documents and Settings\UncleBob\src\share\classes",
a valid result would be a file object representing the file
"C:\Documents and Settings\UncleBob\src\share\classes\com\sun\tools\javac\resources\compiler.properties".

 public FileObject getFileForOutput(Location location,
    String packageName,
    String relativeName,
    FileObject sibling) throws IOException
Gets a {@linkplain FileObject file object} for output
representing the specified relative
name in the specified package in the given location.

Optionally, this file manager might consider the sibling as
a hint for where to place the output.  The exact semantics of
this hint is unspecified.  The JDK compiler, javac, for
example, will place class files in the same directories as
originating source files unless a class file output directory
is provided.  To facilitate this behavior, javac might provide
the originating source file as sibling when calling this
method.

If the returned object represents a {@linkplain
JavaFileObject.Kind#SOURCE source} or {@linkplain
JavaFileObject.Kind#CLASS class} file, it must be an instance
of JavaFileObject .

Informally, the file object returned by this method is
located in the concatenation of the location, package name, and
relative name or next to the sibling argument.  See  getFileForInput  for an example.

 public JavaFileObject getJavaFileForInput(Location location,
    String className,
    Kind kind) throws IOException
Gets a {@linkplain JavaFileObject file object} for input
representing the specified class of the specified kind in the
given location.

 public JavaFileObject getJavaFileForOutput(Location location,
    String className,
    Kind kind,
    FileObject sibling) throws IOException
Gets a {@linkplain JavaFileObject file object} for output
representing the specified class of the specified kind in the
given location.

Optionally, this file manager might consider the sibling as
a hint for where to place the output.  The exact semantics of
this hint is unspecified.  The JDK compiler, javac, for
example, will place class files in the same directories as
originating source files unless a class file output directory
is provided.  To facilitate this behavior, javac might provide
the originating source file as sibling when calling this
method.

 public boolean handleOption(String current,
    Iterator<String> remaining)
Handles one option.  If {@code current} is an option to this
file manager it will consume any arguments to that option from
{@code remaining} and return true, otherwise return false.

 public boolean hasLocation(Location location)
Determines if a location is known to this file manager.

 public String inferBinaryName(Location location,
    JavaFileObject file)
Infers a binary name of a file object based on a location.  The
binary name returned might not be a valid binary name according to
The Java™ Language Specification.

 public boolean isSameFile(FileObject a,
    FileObject b)
Compares two file objects and return true if they represent the
same underlying object.

 public Iterable<JavaFileObject> list(Location location,
    String packageName,
    Set<Kind> kinds,
    boolean recurse) throws IOException
Lists all file objects matching the given criteria in the given
location.  List file objects in "subpackages" if recurse is
true.

Note: even if the given location is unknown to this file
manager, it may not return {@code null}.  Also, an unknown
location may not cause an exception.