Java.io.Writer class in Java Last Updated : 12 Sep, 2023 Comments Improve Suggest changes Like Article Like Report This abstract class for writing to character streams. The only methods that a subclass must implement are write(char[], int, int), flush(), and close(). Most subclasses, however, will override some of the methods defined here in order to provide higher efficiency, additional functionality, or both. Constructor protected Writer() : Creates a new character-stream writer whose critical sections will synchronize on the writer itself. protected Writer(Object lock) : Creates a new character-stream writer whose critical sections will synchronize on the given object. Methods: Writer append(char c) : Appends the specified character to this writer.An invocation of this method of the form out.append(c) behaves in exactly the same way as the invocation out.write(c) Syntax :public Writer append(char c) throws IOException Parameters: c - The 16-bit character to append Returns: This writer Throws: IOException Writer append(CharSequence csq) : Appends the specified character sequence to this writer.An invocation of this method of the form out.append(csq) behaves in exactly the same way as the invocation out.write(csq.toString()) Depending on the specification of toString for the character sequence csq, the entire sequence may not be appended. For instance, invoking the toString method of a character buffer will return a subsequence whose content depends upon the buffer's position and limit. Syntax :public Writer append(CharSequence csq) throws IOException Parameters: csq - The character sequence to append. If csq is null, then the four characters "null" are appended to this writer. Returns: This writer Throws: IOException Writer append(CharSequence csq, int start, int end) : Appends a subsequence of the specified character sequence to this writer.Appends a subsequence of the specified character sequence to this writer Syntax :public Writer append(CharSequence csq, int start, int end) throws IOException Parameters: csq - The character sequence from which a subsequence will be appended. If csq is null, then characters will be appended as if csq contained the four characters "null". start - The index of the first character in the subsequence end - The index of the character following the last character in the subsequence Returns: This writer Throws: IndexOutOfBoundsException IOException abstract void close() : Closes the stream, flushing it first. Once the stream has been closed, further write() or flush() invocations will cause an IOException to be thrown. Closing a previously closed stream has no effect. Syntax :public abstract void close() throws IOException Throws: IOException abstract void flush() : Flushes the stream.If the stream has saved any characters from the various write() methods in a buffer, write them immediately to their intended destination. Then, if that destination is another character or byte stream, flush it. Thus one flush() invocation will flush all the buffers in a chain of Writers and OutputStreams. Syntax :public abstract void flush() throws IOException Throws: IOException void write(char[] cbuf) : Writes an array of characters. Syntax :public void write(char[] cbuf) throws IOException Parameters: cbuf - Array of characters to be written Throws: IOException - If an I/O error occurs abstract void write(char[] cbuf, int off, int len) : Writes a portion of an array of characters. Syntax :public abstract void write(char[] cbuf, int off, int len) throws IOException Parameters: cbuf - Array of characters off - Offset from which to start writing characters len - Number of characters to write Throws: IOException void write(int c) : Writes a single character.The character to be written is contained in the 16 low-order bits of the given integer value; the 16 high-order bits are ignored. Subclasses that intend to support efficient single-character output should override this method. Syntax :public void write(int c) throws IOException Parameters: c - int specifying a character to be written Throws: IOException void write(String str) : Writes a string. Syntax :public void write(String str) throws IOException Parameters: str - String to be written Throws: IOException void write(String str, int off, int len) : Writes a portion of a string. Syntax :public void write(String str, int off, int len) throws IOException Parameters: str - A String off - Offset from which to start writing characters len - Number of characters to write Throws: IndexOutOfBoundsException Program : Java //Java program demonstrating Writer methods import java.io.IOException; import java.io.PrintWriter; import java.io.Writer; class WriterDemo { public static void main(String[] args) throws IOException { Writer wr=new PrintWriter(System.out); char c[] = {'B','C','D','E','F'}; CharSequence cs = "JKL"; String str = "GHI"; //illustrating write(int c) wr.write(65); //flushing the stream wr.flush(); //illustrating write(char[] c,int off,int len) wr.write(c); wr.flush(); //illustrating write(String str,int off,int len) wr.write(str); wr.flush(); //illustrating append(Charsequence cs,int start,int end) wr.append(cs); wr.flush(); //illustrating append(int ch) wr.append('M'); wr.flush(); //closing the stream wr.close(); } } Output : ABCDEFGHIJKLM Comment More infoAdvertise with us Next Article Java.io.Writer class in Java N Nishant Sharma Improve Article Tags : Java Practice Tags : Java Similar Reads Java Tutorial Java is a high-level, object-oriented programming language used to build web apps, mobile applications, and enterprise software systems. It is known for its Write Once, Run Anywhere capability, which means code written in Java can run on any device that supports the Java Virtual Machine (JVM).Java s 10 min read Java Interview Questions and Answers Java is one of the most popular programming languages in the world, known for its versatility, portability, and wide range of applications. Java is the most used language in top companies such as Uber, Airbnb, Google, Netflix, Instagram, Spotify, Amazon, and many more because of its features and per 15+ min read Java OOP(Object Oriented Programming) Concepts Java Object-Oriented Programming (OOPs) is a fundamental concept in Java that every developer must understand. It allows developers to structure code using classes and objects, making it more modular, reusable, and scalable.The core idea of OOPs is to bind data and the functions that operate on it, 13 min read Arrays in Java Arrays in Java are one of the most fundamental data structures that allow us to store multiple values of the same type in a single variable. They are useful for storing and managing collections of data. Arrays in Java are objects, which makes them work differently from arrays in C/C++ in terms of me 15+ min read Inheritance in Java Java Inheritance is a fundamental concept in OOP(Object-Oriented Programming). It is the mechanism in Java by which one class is allowed to inherit the features(fields and methods) of another class. In Java, Inheritance means creating new classes based on existing ones. A class that inherits from an 13 min read Collections in Java Any group of individual objects that are represented as a single unit is known as a Java Collection of Objects. In Java, a separate framework named the "Collection Framework" has been defined in JDK 1.2 which holds all the Java Collection Classes and Interface in it. In Java, the Collection interfac 15+ min read Java Exception Handling Exception handling in Java allows developers to manage runtime errors effectively by using mechanisms like try-catch block, finally block, throwing Exceptions, Custom Exception handling, etc. An Exception is an unwanted or unexpected event that occurs during the execution of a program, i.e., at runt 10 min read Java Programs - Java Programming Examples In this article, we will learn and prepare for Interviews using Java Programming Examples. From basic Java programs like the Fibonacci series, Prime numbers, Factorial numbers, and Palindrome numbers to advanced Java programs.Java is one of the most popular programming languages today because of its 8 min read Java Interface An Interface in Java programming language is defined as an abstract type used to specify the behaviour of a class. An interface in Java is a blueprint of a behaviour. A Java interface contains static constants and abstract methods. Key Properties of Interface:The interface in Java is a mechanism to 12 min read Polymorphism in Java Polymorphism in Java is one of the core concepts in object-oriented programming (OOP) that allows objects to behave differently based on their specific class type. The word polymorphism means having many forms, and it comes from the Greek words poly (many) and morph (forms), this means one entity ca 7 min read Like