Using the new keyword and the String constructor:


In Java, you can create string objects using the new keyword along with the String constructor. 

This method provides flexibility in dynamically creating strings based on variables or user input. 

Here are some key details about using the new keyword and the String constructor:


Creating String Objects:

The new keyword followed by the String constructor is used to create a new string object.

The constructor takes a string argument, which can be a string literal, a variable, or any valid string expression.

Example:


String name = new String("John Doe");

In the above example, the new keyword creates a new string object with the value "John Doe". The string object is assigned to the variable name.


Creating Objects from Variables or Expressions:

The value passed to the String constructor can be a variable or any valid string expression.

This allows you to dynamically create strings based on runtime values or manipulate existing strings.

Example:


String firstName = "John"; 
String lastName = "Doe";
String fullName = new String(firstName + " " + lastName);

In the above example, the string object referred to by fullName is created by  concatenating the firstName, a space, and the lastName.

 This demonstrates the flexibility of using the String constructor to construct strings from variables or expressions.


Differences from String Literals:

When creating strings using the new keyword and the String constructor, a new string object is always created, even if an equivalent string already exists in the string pool.

This means that the newly created object will occupy a separate memory location, unlike string literals that can be interned and reused from the string pool.

Example:


String str1 = "Hello"; 
String str2 = new String("Hello");
 System.out.println(str1 == str2); // Output: false

In the above example, str1 is a string literal that exists in the string pool, while str2 is a new String object created using the new keyword . 

The comparison str1 == str2 evaluates to false because they refer to different string objects, despite having the same value.


Using the new keyword and the String constructor provides flexibility in creating string objects dynamically and manipulating strings based on variables or expressions. 

However, it's important to note that this method creates new string objects regardless of whether an equivalent string already exists in the string pool.