Java Convert an Object to String

Last Updated : 17 Feb 2026

We can convert Object to String in Java by using the toString() method of Object class or String.valueOf(object) method.

We can convert an object to String in Java whether it is user-defined class, StringBuilder, StringBuffer or anything else.

There are the following ways to convert object to string in Java:

Method	Description
Object.toString()	Provides a textual representation of the object, detailing its characteristics or state.
String.valueOf()	A static function of the String class that transforms an object into its string form.
+ Operator	It facilitates combining any data type with a string, creating a new string that includes the added content.
String.join()	Merges an array of elements into a single string, utilizing a specified separator between each element's string form.

Using toString() Method

The toString() method in Java enables the conversion of user-defined class objects into descriptive strings, that aids in debugging and enhances code readability.

Filename: ToStringMethod.java

class Student {
    private String name;
    private int age;
    // Constructor to initialize the Student object
    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }
    // Override the toString() Method to provide a custom string representation of the Student object
    @Override
    public String toString() {
        return "Student{" +
               "name='" + name + '\'' +
               ", age=" + age +
               '}';
    }
}
public class ToStringMethod {
    public static void main(String[] args) {
        // Create a new Student object
        Student student = new Student("Alice", 20);
        // Convert the Student object to a String using the toString() method
        // This is automatically called when we pass the student object to System.out.println()
        System.out.println(student);
    }
}

Output:

Student{name='Alice', age=20}

Java Program to Convert Object of Predefined Class(StringBuilder) to String

Using Sting.valueOf() Method

The valueOf() method in Java is a String class static method. It converts different types of values, including objects and Strings. When working with objects of predefined classes such as StringBuilder, the valueOf() method can convert these objects into strings. Let's understand it with an example.

Filename: ValueOfMethod.java

class TeamMember {
  private String firstName;
  private String lastName;
  TeamMember(String firstName, String lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
  }
  public String getFirstName() {
    return firstName;
  }
  public void setFirstName(String firstName) {
    this.firstName = firstName;
  }
  public String getLastName() {
    return lastName;
  }
  public void setLastName(String lastName) {
    this.lastName = lastName;
  }
  @Override
  public String toString() {
    return "TeamMember [firstName=" + firstName + ", lastName=" + lastName + "]";
  }
  public String getStringRepresentation() {
    return toString();
  }
  public String getFullName() {
    return firstName + " " + lastName;
  }
}
public class ValueOfMethod {
  public static void main(String[] args) {
    TeamMember teamMember = new TeamMember("Jainey", "Jain");
    String stringRepresentation = teamMember.getStringRepresentation(); // Utilizing getStringRepresentation method
    System.out.println("String representation: " + stringRepresentation);
    String fullName = teamMember.getFullName(); // Using getFullName to obtain the full name
    System.out.println("TeamMember's full name: " + fullName);
  }
}

Output:

String representation: TeamMember [firstName=Jainey, lastName=Jain]
TeamMember's full name: Jainey Jain

Using + Operator

In Java, the + Operator is overloaded as a concatenation operator for strings. When used with strings and other data types, including objects, the + Operator implicitly converts the non-string elements to strings. The conversion often involves calling the toString() Method of the concatenated object.

Filename: ObjToString.java

class Book {
    private String title;
    private String author;
    // Constructor
    public Book(String title, String author) {
        this.title = title;
        this.author = author;
    }
    // Override the toString() method
    @Override
    public String toString() {
        return "Book{" +
               "title='" + title + '\'' +
               ", author='" + author + '\'' +
               '}';
    }
}
public class ObjToString {
    public static void main(String[] args) {
        // Create a new Book object
        Book book = new Book("1984", "George Orwell");
        // Convert the Book object to a String using the + Operator
        String bookString = "The details of the book are: " + book; // Implicitly calls book.toString()
        // Print the string representation of the Book object
        System.out.println(bookString);
    }
}

Output:

The details of the book are: Book{title='1984', author='George Orwell'}

Using String.join() Method

The join() method in Java is a static method of the String class used to concatenate the elements of an array or iterable into a single String, with a specified delimiter between each element. While the primary use of join() is for concatenating strings. It can also indirectly convert an object to a string, given that the object's toString() Method is effectively utilized.

Filename: JoinMethod.java

class Person {
    private String name;
    private int age;
    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
    @Override
    public String toString() {
        return "Person{name='" + name + "', age=" + age + "}";
    }
}
public class JoinMethod {
    public static void main(String[] args) {
        // Create an array of Person objects
        Person[] people = {
            new Person("Alice", 30),
            new Person("Bob", 25),
            new Person("Charlie", 35)
        };
        // Convert each Person object in the array to a String
        String[] peopleStrings = new String[people.length];
        for (int i = 0; i < people.length; i++) {
            peopleStrings[i] = people[i].toString();
        }
        //Use join() to concatenate the string representations of the Person objects, separated by a delimiter
        String allPeople = String.join(", ", peopleStrings);
        // Print the concatenated String
        System.out.println(allPeople);
    }
}

Output:

Person{name='Alice', age=30}, Person{name='Bob', age=25}, Person{name='Charlie', age=35}

Java Program to Convert User-defined Class Object into String

Let's see the simple code to convert String to Object in Java.

ObjectToStringExample.java

class Emp{}  
public class ObjectToStringExample{  
public static void main(String args[]){  
Emp e=new Emp();  
String s=e.toString();  
String s2=String.valueOf(e);  
System.out.println(s);  
System.out.println(s2);  
}}  

Output:

Emp@2a139a55
Emp@2a139a55

In the above Java program, we observe that a reference id of Emp class is printed on the console.

Java Program to Convert Pre-Defined StringBuilder Class Object into String

Let's see the simple code to convert StringBuilder object to String in Java.

ObjectToStringExample2.java

public class ObjectToStringExample2{  
public static void main(String args[]){  
String s="hello";  
StringBuilder sb=new StringBuilder(s);  
sb.reverse();  
String rev=sb.toString();//converting StringBuilder to String  
System.out.println("String is: "+s);  
System.out.println("Reverse String is: "+rev);  
}}  

Output:

String is: hello
Reverse String is: olleh

Now we can write the code to check the palindrome string.

ObjectToStringExample3.java

public class ObjectToStringExample3{  
public static void main(String args[]){  
String s="nitin";  
StringBuilder sb=new StringBuilder(s);  
sb.reverse();  
String rev=sb.toString();//converting StringBuilder to String  
if(s.equals(rev)){  
System.out.println("Palindrome String");  
}else{  
System.out.println("Not Palindrome String");  
}  
}}  

Output:

Palindrome String

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