| Package | Description | 
|---|---|
| java.io | Provides for system input and output through data streams,
serialization and the file system. | 
| java.lang | Provides classes that are fundamental to the design of the Java
 programming language. | 
| java.nio | Defines buffers, which are containers for data, and provides an overview of the
other NIO packages. | 
| java.rmi.server | Provides classes and interfaces for supporting the server
side of RMI. | 
| java.time.format | 
 Provides classes to print and parse dates and times. | 
| java.util | Contains the collections framework, legacy collection classes, event model,
date and time facilities, internationalization, and miscellaneous utility
classes (a string tokenizer, a random-number generator, and a bit array). | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | BufferedWriterWrites text to a character-output stream, buffering characters so as to
 provide for the efficient writing of single characters, arrays, and strings. | 
| class  | CharArrayWriterThis class implements a character buffer that can be used as an Writer. | 
| class  | FileWriterConvenience class for writing character files. | 
| class  | FilterWriterAbstract class for writing filtered character streams. | 
| class  | OutputStreamWriterAn OutputStreamWriter is a bridge from character streams to byte streams:
 Characters written to it are encoded into bytes using a specified  charset. | 
| class  | PipedWriterPiped character-output streams. | 
| class  | PrintStreamA  PrintStreamadds functionality to another output stream,
 namely the ability to print representations of various data values
 conveniently. | 
| class  | PrintWriterPrints formatted representations of objects to a text-output stream. | 
| class  | StringWriterA character stream that collects its output in a string buffer, which can
 then be used to construct a string. | 
| class  | WriterAbstract class for writing to character streams. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | StringBufferA thread-safe, mutable sequence of characters. | 
| class  | StringBuilderA mutable sequence of characters. | 
| Modifier and Type | Method and Description | 
|---|---|
| Appendable | Appendable. append(char c)Appends the specified character to this Appendable. | 
| Appendable | Appendable. append(CharSequence csq)Appends the specified character sequence to this Appendable. | 
| Appendable | Appendable. append(CharSequence csq,
      int start,
      int end)Appends a subsequence of the specified character sequence to this
 Appendable. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | CharBufferA char buffer. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | LogStreamDeprecated. 
 no replacement | 
| Modifier and Type | Method and Description | 
|---|---|
| void | DateTimeFormatter. formatTo(TemporalAccessor temporal,
        Appendable appendable)Formats a date-time object to an  Appendableusing this formatter. | 
| Modifier and Type | Method and Description | 
|---|---|
| Appendable | Formatter. out()Returns the destination for the output. | 
| Constructor and Description | 
|---|
| Formatter(Appendable a)Constructs a new formatter with the specified destination. | 
| Formatter(Appendable a,
         Locale l)Constructs a new formatter with the specified destination and locale. | 
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For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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