Skip to main content

Java Exception Handling MCQ Test

  Loading…
Post a Comment

StringBuffer Class in Java

StringBuffer Class in Java

`StringBuffer` is a class in Java that represents a mutable sequence of characters. Unlike the `String` class, which is immutable, a `StringBuffer` allows for the modification of its content without creating a new object. This makes it more efficient for situations where frequent modifications to a sequence of characters are required.


Key Features:


1. Mutability:

   - `StringBuffer` objects are mutable, meaning the content of a `StringBuffer` instance can be modified after its creation.


2. Synchronization:

   - `StringBuffer` is synchronized, making it thread-safe. This ensures that multiple threads can safely access and modify a `StringBuffer` object without interference.


3. Performance Considerations:

   - While `StringBuffer` provides mutability, it might have performance overhead due to synchronization. If thread safety is not required, the non-synchronized class `StringBuilder` should be considered for better performance.


Common Methods:


Here are some commonly used methods of the `StringBuffer` class:


1. Constructor:


- `StringBuffer()`

  - Creates an empty `StringBuffer` with the default initial capacity (16 characters).


  • StringBuffer buffer = new StringBuffer();


2. Appending Content:


- `append(String str)`

  - Appends the specified string to the end of the `StringBuffer`.


buffer.append("Hello");

buffer.append(" World");


3. Inserting Content:


- `insert(int offset, String str)`

  - Inserts the specified string at the specified offset.


  • buffer.insert(5, " Java");


 4. Deleting Content:


- `delete(int start, int end)`

  - Deletes the characters between the specified `start` (inclusive) and `end` (exclusive) indices.


buffer.delete(6, 11);



5. Reversing Content:


- `reverse()`

  - Reverses the characters in the `StringBuffer`.

  • buffer.reverse();


6. Capacity Management:

- `capacity()`

  - Returns the current capacity of the `StringBuffer`.

  • int capacity = buffer.capacity();


- `ensureCapacity(int minCapacity)`

  - Ensures that the capacity of the `StringBuffer` is at least equal to the specified minimum capacity.

  • buffer.ensureCapacity(50);


7. Converting to String:

- `toString()`

  - Converts the `StringBuffer` to a `String`.


  • String result = buffer.toString();



 Example Usage:



// Creating a StringBuffer

StringBuffer buffer = new StringBuffer();


// Appending content

buffer.append("Hello");

buffer.append(" World");


// Inserting content

buffer.insert(5, " Java");


// Deleting content

buffer.delete(6, 11);


// Reversing content

buffer.reverse();


// Converting to String

String result = buffer.toString();



The `StringBuffer` class provides a flexible and thread-safe way to work with mutable character sequences in Java. If synchronization is not required, consider using the `StringBuilder` class for potentially better performance.

Labels:

Comments

Post a Comment

Popular posts from this blog

Passing and Returning Objects in Java Methods

Passing and Returning Objects in Java Methods In Java, objects can be passed as parameters to methods and returned from methods just like other primitive data types. This allows for flexibility and the manipulation of object state within methods. Let's explore how passing and returning objects work in Java. Passing Objects as Parameters When you pass an object as a parameter to a method, you are essentially passing a reference to that object. This means that changes made to the object inside the method will affect the original object outside the method.  Example: class Car {     String model;     Car(String model) {         this.model = model;     } } public class CarProcessor {     // Method to modify the Car object     static void modifyCar(Car car, String newModel) {         car.model = newModel;     }     public static void main(String[] args) {       ...
Post a Comment
Read more

Chained Exceptions

 Chained exceptions, also known as nested exceptions, allow you to associate one exception with another. This feature is useful when you want to provide more context or information about the cause of an exception. In Java, you can chain exceptions using constructors that take a `Throwable` (or its subclasses) as an argument. Syntax: try {     // Code that may throw an exception } catch (ExceptionType1 e1) {     throw new ExceptionType2("Additional information", e1); } Explanation: - Inside a `catch` block, you can create a new exception object and pass the original exception (`e1`) as the cause. - The chained exception (`ExceptionType2`) includes a message and the original exception (`e1`) as its cause. - This technique allows you to preserve the original exception's stack trace and context while providing additional information about the higher-level exception. - Chained exceptions can be caught and processed at higher levels of the call stack, allowing for bet...
Post a Comment
Read more