Understanding Java String, Java StringBuffer, and Java StringBuilder

An essential feature of a programming language is a string. If you are displaying some content on your console, you need strings to do that. Not only in Java, has a maximum of programming languages worked with strings for multiple purposes. If you want to learn Java, there are many online courses available on the internet that provide you with . Strings allow users to do various operations like concatenation, comparison, slicing, replacing, and many formatting actions. Let us discuss what string actually is and how it differs from StringBuffer and StringBuilder.

Strings in Java:

Strings represent the collection of characters. We can perform multiple operations with strings since strings are immutable. It means we can't make changes on a string. Instead, a new string instance will be created with the changes you have done. Once you declare a string, the Java virtual machine (JVM) will look into the string pool, searching for similar string values. If no match is found, then it creates a new string object reference. The string uses a UTF-16 encoding system, which covers most of the alphanumeric values and symbols, making it easier to declare various strings.

Strings are declared using " "( double quotation) by default. Generally, strings are declared using the following syntax:

String str = " abs";

StringBuffer in Java:

StringBuffer allows users to create mutable strings, which means we can modify the existing string. You can insert or delete characters of a StringBuffer to manipulate it. The size of the StringBuffer can be automatically increased or decreased by itself. String buffers offer append, insert, delete, reverse, and capacity methods to modify the string buffer. StringBuffer can be declared in the following ways:

StringBuffer str = new StringBuffer();

This will create an empty string buffer with an initial capacity of 16 characters.

StringBuffer str = new StringBuffer(String string);

This syntax will create a string buffer with the content of the string passed as a parameter.

StringBuffer str = new StringBuffer(int size); This will create a string buffer with the size of the parameter passed.

StringBuilder in Java:

String builders are more similar to string buffers. It has all the methods used in the string buffer class. These string builders are introduced in Java version 1.5. String builders are non-synchronized, which means two threads can simultaneously call the methods of string builder. The model syntax of declaring string builder is mentioned below:

public final class StringBuilder

extends Object

implements Serializable, CharSequence

The StringBuilder declaration can be done in the following ways:

StringBuilder() - Constructs an empty string builder with an initial capacity of 16 characters.

StringBuilder(int capacity) - Creates a string builder with an initial capacity specified by the capacity of the passing argument.

StringBuilder(CharSequence seq) – creates a StringBuilder that matches the character sequence.

StringBuilder(String str) – Creates a string builder with specified content of the passed parameter.

String vs. StringBuffer vs. StringBuilder:

Strings can take more space while concatenating with more strings. Whereas string buffer and StringBuilder are fast working and consume less memory for concatenation operations.

Strings create new instances for each newly formed string and use the default string pool to search for the existing string object instances. String buffers and StringBuilder use heap memory for creating object instances.

String overload equals() method to compare two strings. String buffer and StringBuilder don't have equals() method.

String uses the + operator externally to do the concatenation process, and StringBuffer and StringBuilder use the + operator internally.

Strings don't provide thread safety, and it is non-synchronized. StringBuffers are thread-safe and synchronized, but StringBuilder is non-synchronized, which makes StringBuilder work faster than StringBuffer.

Strings are not applicable in non-multi-threaded environments, so that we can use StringBuffer or StringBuilder.

Bottom line:

The abovementioned explain strings, StringBuffer, and StringBuilder in Java. To become an expert in Java, complete , which provides you with the practical implementation of Java programming.