Java Immutable String

Example of Immutable String in java

Example of Immutable String in java

 // Java example of Immutable String

public class Main {	
    public static void main(String args[]){  		 
	  String str="Welcome ";  
	  s.concat("To India");  //The string is added at the end by the concat() method.
	  System.out.println(s); //it will print welcome instead of India due to Immutable String 
  } 
}

Welcome  

Example of String explicitly assign it to the reference variable

Example of String explicitly assign it to the reference variable in java

public class Main {	
    public static void main(String args[]){  		 
	  String str="Welcome";  
	  str= str.concat("To India");  //if we explicitly assign it to the reference variable
	  System.out.println(str);   //it will print Welcome To India
  } 
}

Welcome To India 

Why String objects are immutable in Java

Since Java makes use of the String literal concept. Assume there are five reference variables, all of which point to the same thing, "Sachin." All reference variables will be impacted if one reference variable alters the value of the object. Because of this, String objects in Java are immutable.

Several String characteristics make String objects immutable.

• ClassLoader : A String object is used as an argument by a Java ClassLoader. Consider the possibility that the value could change and the class that is supposed to be loaded could change if the String object is modifiable.String is immutable in order to prevent this kind of misunderstanding.




• Thread Safe : Since the String object cannot be changed, we don't need to worry about the synchronization needed when using it in multiple threads.
• Security : Immutable String objects load the appropriate class to prevent additional errors, as we have seen with class loading. As a result, the application program becomes more secure. Think about a payment software illustration. Because String objects are immutable, no outsider can change the username or password. The application program may become more secure as a result.
• Heap Space : The immutability of String contributes to a reduction in the amount of heap memory used. The JVM checks to see if the value is already present in the String pool when we attempt to declare a new String object. The new object is given the same value if it already exists. Java can effectively utilize the heap space thanks to this feature.

Why String class cannot be override in Java

The String class's final status is due to the fact that its methods cannot be overridden by any other classes. In order to give the new String objects and the old String objects the same features.