What is the use of StringBuffer in Java?

Why do we use StringBuffer and StringBuilder in Java?

The StringBuffer and StringBuilder classes are used when there is a necessity to make a lot of modifications to Strings of characters. … It is recommended to use StringBuilder whenever possible because it is faster than StringBuffer. However, if the thread safety is necessary, the best option is StringBuffer objects.

When should we use StringBuffer?

When to use which one :

If a string can change and will be accessed from multiple threads, use a StringBuffer because StringBuffer is synchronous, so you have thread-safety. If you don’t want thread-safety than you can also go with StringBuilder class as it is not synchronized.

Why StringBuilder is used in Java?

The StringBuilder in Java represents a mutable sequence of characters. Since the String Class in Java creates an immutable sequence of characters, the StringBuilder class provides an alternative to String Class, as it creates a mutable sequence of characters.

How does StringBuffer save memory?

String will always create new memory space, whereas StringBuffer will not, it will update the existing memory whenever we append with new value. new StringBuffer(“A ” + “B ” + “C ” + “D ” + “E ” + “F”).

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Is String is thread safe in Java?

Every immutable object in Java is thread safe ,that implies String is also thread safe . String can not be used by two threads simultaneously. String once assigned can not be changed. StringBuffer is mutable means one can change the value of the object .

Is String mutable in Java?

In java String are immutable. No mutable strings. possible duplicate of String is immutable.

Why is StringBuffer mutable in Java?

Answer: The String class is considered as immutable, so that once it is created a String object cannot be changed. If there is a necessity to make alot of modifications to Strings of characters then StringBuffer should be used.

What makes Java more efficient?

Java’s efficiency largely comes from its Just-In-Time (JIT) compiler and support for concurrency. The JIT compiler is a part of the Java Runtime Environment. It improves performance of Java programs by compiling bytecodes into native machine code “just in time” to run.

What is String method in Java?

All String Methods

Method Description Return Type
toString() Returns the value of a String object String
toUpperCase() Converts a string to upper case letters String
trim() Removes whitespace from both ends of a string String
valueOf() Returns the string representation of the specified value String

Why do we need StringBuilder?

StringBuilder is a mutable sequence of characters. StringBuilder is used when we want to modify Java strings in-place. StringBuilder has methods such as append() , insert() , or replace() that allow to modify strings. …

What does toString () do in Java?

The toString method returns a String representation of an object in Java. By default, the toString method returns the name of the object’s class plus its hash code. Here, you find out how to use the toString method and how to override it in your own classes to create more useful strings.


Can we modify a String in Java?

Strings are immutable. Once you have created a string you cannot later change that string object. Java uses pass-by-value, not pass-by-reference. When you assign a new value to s in your method it only modifies the local s , not the original s in the calling code.