Which Class is immutable Other than string?

Which class is immutable other than string: In Java, there are several classes other than String that are immutable, some of them are:

What is String in java?

In Java, a String is a sequence of characters that represents a text value. It is a built-in class in Java, part of the java.lang package, and is widely used in Java programming.

Strings in Java are immutable, meaning that once a String object is created, its value cannot be changed. Whenever a modification is made to a String, a new String object is created with the new value, leaving the original String object unchanged. This immutability makes Strings thread-safe and allows them to be shared among multiple threads without the need for synchronization.

Strings in Java can be created using the String literal syntax, like this:

String str = "Hello, World!";

Or they can be created using the String class constructor, like this:

String str = new String("Hello, World!");

The String class provides many useful methods for working with strings, such as substring, length, equals, and compareTo. String concatenation can be done using the + operator or the concat method.

In addition to the basic String class, Java also provides several other classes for working with strings, such as StringBuilder and StringBuffer, which provide mutable versions of the String class for cases where performance is a concern.

Which Class is immutable Other than string

  1. java.lang.Integer, java.lang.Float, java.lang.Double, java.lang.Long, java.lang.Short, java.lang.Character, java.lang.Boolean: All of these classes are wrappers for their corresponding primitive data types and are immutable.
  2. java.time.LocalDate, java.time.LocalTime, java.time.LocalDateTime, java.time.ZonedDateTime, java.time.OffsetDateTime: All of these classes are part of the Java 8 Date and Time API and are immutable.
  3. java.math.BigDecimal, java.math.BigInteger: These classes are used for arbitrary-precision arithmetic and are immutable.
  4. java.awt.Color: This class represents a color in the RGB color space and is immutable.
  5. java.net.URI: This class represents a Uniform Resource Identifier (URI) and is immutable.

Immutable classes have several benefits such as thread safety, security, caching, and they can be used as keys in maps or elements in sets, without worrying about their values being changed.

Immutable Class in Java

In Java, an immutable class is a class whose instances cannot be modified once they are created. Immutable classes are thread-safe and can be shared among multiple threads without the need for synchronization. Once an immutable object is created, its state cannot be changed, which makes it easy to reason about its behavior and guarantees its correctness.

To create an immutable class in Java, we need to follow the following guidelines:

  1. Declare the class final, so it cannot be sub classed and its behavior cannot be modified.
  2. Declare all instance variables private and final, so they cannot be changed once initialized.
  3. Do not provide any public setters or mutable methods that can modify the state of the object.
  4. If any fields are mutable objects, return defensive copies of those objects in any methods that return them.
  5. Ensure that the class can be properly initialized by using constructors and static factory methods.

Here is an example of an immutable class in Java:

public final class Person {
    private final String name;
    private final int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }
}

In this example, the Person class is declared as final and all its instance variables are declared as private and final. The class has a constructor that initializes its instance variables and it also has getter methods that return the values of the instance variables. Once an instance of the Person class is created, its state cannot be changed.

Use of immutable Class in Java

Immutable classes in Java have several benefits and are widely used in Java programming. Some of the benefits of using immutable classes are:

  1. Thread safety: Immutable classes are thread-safe and can be safely shared among multiple threads without the need for synchronization.
  2. Cache-friendly: Immutable objects are cache-friendly because they have a constant value, which can be easily cached for performance reasons.
  3. Security: Immutable classes can help improve security by preventing malicious code from modifying their state.
  4. Robustness: Immutable classes are more robust than mutable classes because their state cannot be changed accidentally or intentionally.
  5. Easy to reason about: Immutable classes are easier to reason about because their behavior is predictable and does not change over time.

Some of the common use cases for immutable classes in Java are:

  1. Value objects: Immutable classes are often used to represent value objects, such as dates, times, and currency amounts.
  2. Configuration objects: Immutable classes can be used to represent configuration objects, which contain a fixed set of properties that cannot be changed at runtime.
  3. Cache keys: Immutable classes are often used as cache keys because their value is constant and can be easily cached for performance reasons.
  4. Functional programming: Immutable classes are used extensively in functional programming because they can be safely shared among multiple functions without the need for synchronization.

Overall, immutable classes are an important tool in Java programming, and their use can help improve the robustness, performance, and security of software systems.

Advantages of immutable Class in Java

Immutable classes in Java have several advantages, including:

  1. Thread-safety: Immutable classes are inherently thread-safe because their state cannot be changed once they are created. They can be safely shared among multiple threads without the need for synchronization, making it easier to write concurrent programs.
  2. Security: Immutable classes can help improve security by preventing malicious code from modifying their state. This is especially important in situations where sensitive information needs to be protected.
  3. Robustness: Immutable classes are more robust than mutable classes because their state cannot be changed accidentally or intentionally. This makes them easier to use and less prone to bugs and errors.
  4. Performance: Immutable classes can offer better performance in certain situations, such as when they are used as keys in maps or elements in sets. Because their state is constant, they can be cached more easily, which can improve performance.
  5. Easy to reason about: Immutable classes are easier to reason about because their behavior is predictable and does not change over time. This makes them easier to understand and debug.
  6. Compatibility with existing code: Immutable classes are often compatible with existing code because they do not rely on mutable state. This can make it easier to integrate them into existing systems.

Overall, the use of immutable classes in Java can lead to more robust, secure, and performant software systems that are easier to reason about and less prone to errors.

String important Coding Questions

Strings are a fundamental data type in Java, and there are many important coding questions that involve working with strings. Here are a few examples:

  1. Reverse a String: Write a program that takes a String as input and returns the same string with its characters reversed.
  2. Check if two Strings are anagrams: Write a program that takes two strings as input and returns true if they are anagrams (contain the same characters in a different order) or false if they are not.
  3. Find the first non-repeating character in a String: Write a program that takes a String as input and returns the first non-repeating character in the String, or null if there is no such character.
  4. Check if a String is a palindrome: Write a program that takes a String as input and returns true if it is a palindrome (reads the same backward as forward) or false if it is not.
  5. Count the number of occurrences of a substring in a String: Write a program that takes two Strings as input, one representing a longer string and the other representing a substring, and returns the number of times the substring appears in the longer string.
  6. Remove duplicates from a String: Write a program that takes a String as input and returns a new String with all duplicates removed.
  7. Find the longest common prefix of two Strings: Write a program that takes two Strings as input and returns the longest common prefix (the longest sequence of characters that is common to both strings).

These are just a few examples of the many important coding questions that involve working with strings in Java.

Join TelegramJoin Now
Home PageFull Stack With Java

Leave a Comment