10 Tips To Override Tostring() Method Inward Coffee - Tostringbuilder Netbeans Eclipse

Java toString method

toString method inwards Java is used to furnish clear as well as concise information almost Object inwards human readable format. Influenza A virus subtype H5N1 correctly overridden toString method tin assistance inwards logging as well as debugging of Java program past times providing valuable as well as meaningful information. Since toString() is defined inwards java.lang.Object cast as well as its default implementation don't furnish much information, it's ever a best exercise to override the toString method inwards sub class. In fact, if yous are creating value cast or domain cast e.g. Order, Trade or Employee,  always override equals,hashCode, compareTo as well as toString method inwards Java.  By default toString implementation produces output inwards the cast package.class@hashCode e.g. for our toString() example, Country class’ toString() method volition impress test.Country@18e2b22 where 18e2b22 is hashCode of an object inwards hex format, if yous telephone telephone hashCode method it volition render 26094370, which is decimal equivalent of 18e2b22. This information is non rattling useful piece troubleshooting whatever problem. 

Let’s run into a existent life illustration where yous are troubleshooting network connectivity issues, inwards instance of this yous desire to know which host as well as port your organization is trying to connect as well as if Socket or ServerSocket cast exclusively impress default toString information than its impossible to figure out the actual problem, but alongside a decent toString implementation they tin impress useful information similar hostname as well as port. 

In this Java  tutorial nosotros volition run into roughly tips to override toString method alongside code examples.

How to override toString method inwards Java:

overriding whatever method inwards Java, yous withdraw to follow rules of method overriding. Any agency at that spot are many agency to implement or override toString() method e.g.  You tin write this method manually, yous tin utilization IDE similar Netbeans as well as Eclipse to generate toString method or yous tin utilization Apache park ToStringBuilder to generate toString method inwards multiple styles similar unmarried line, multi-line etc. Here are few points to recall piece overriding toString() method inwards Java, which volition assistance yous to acquire most from your toString() implementation.

Print formatted engagement e.g. dd-MM-yy instead of raw date

This is rattling helpful tip piece overriding Java’s toString() method. Since toString() of java.util.Date cast does non impress formatted engagement as well as includes lots of details which is non ever necessary. If yous are using a particular DateFormat e.g. dd-MM-yy inwards your application, they yous definitely desire to run into dates on that format instead of default. IDE unremarkably does non generate formatted Date output as well as this is something yous withdraw to do past times yourself  but its worth of effort. See How to impress Date inwards ddMMyy format inwards Java for to a greater extent than details on formatting Date inwards Java. You tin either utilization SimpleDateFormat cast or Joda Date fourth dimension library for this purpose.

Document toString format

If your toString() method is non printing information inwards price of field=value, Its proficient persuasion to document format of toString, peculiarly for value objects similar Employee or Student. For illustration if toString() method of Employee prints "John-101-Sales-9846387321" than its proficient persuasion to specify format every bit "name-id-department-contact", but at the same fourth dimension don't allow your client extract information from toString() method as well as yous should ever furnish corresponding getter methods similar getName(), getId(), getContact() etc, because extracting information from toString() representation of Object is delicate as well as fault prone as well as client should ever a cleaner agency to asking information.

Use StringBuilder to generate toString output

If yous writing code for toString() method inwards Java, thus utilization StringBuilder to append private attribute.  If yous are using IDE similar Eclipse, Netbeans or IntelliJ thus too using  StringBuilder as well as append() method instead of + operator to generate toString method is proficient way. By default both Eclipse as well as Netbeans generate toString method alongside concatenation operator .

Use @Override annotation

Using @Override notation piece overriding method inwards Java is i of the best exercise inwards Java. But this tip is non every bit of import every bit it was inwards instance of overriding equals() as well as compareTo() method, every bit overloading instead of overriding tin do to a greater extent than subtle bugs there. Anyway it’s best to using @Override annotation.

Print contents of Array instead of printing array object

Array is an object inwards Java but it doesn’t override toString method as well as when yous impress array, it volition utilization default format which is non rattling helpful because nosotros want  to run into contents of Array. By the agency this is roughly other argue why char[] array are preferred over String for storing sensitive information e.g. password. Take a 2nd to run into if printing content of array helps your user or non as well as if it brand feel than impress contents instead of array object itself. Apart from functioning argue prefer Collection similar ArrayList or HashSet over Array for storing other objects.

Bonus Tips

Here are few to a greater extent than bonus tips on overriding toString method inwards Java

1. Print output of toString inwards multiple line of piece of occupation or unmarried line of piece of occupation based upon it length.

2. Include amount qualified advert of cast inwards toString representation e.g. package.class to avoid whatever confusion/

3. You tin either skip zip values or demonstrate them, its amend to travel out them. Sometime they are useful every bit they quest which fields are zip at the fourth dimension of whatever incident e.g. NullPointerException.

4. Use fundamental value format similar member.name=member.value every bit most of IDE too follows that.

5. Include inherited members if yous affair they furnish must bring information inwards nipper class.

6. Sometime an object contains many optional as well as mandatory parameters similar nosotros shown inwards our Builder designing example, when its non practically possible to impress all fields inwards those cases printing a meaningful information, non necessary fields is better.

 toString Example inwards Java 

We volition utilization next cast to demonstrate our toString examples for Netbeans, Eclipse as well as Apache's ToStringBuilder utility.

/**
 * Java program to demonstrate How to override toString() method inwards Java.
 * This Java programme shows How tin yous utilization IDE similar Netbeans or Eclipse
 * as well as Open beginning library similar Apache park ToStringBuilder to

 * override toString inwards Java.
 *
 * @author .blogspot.com
 */

public class Country{
    private String name;
    private String capital;
    private long population;
    private Date independenceDay;

    public Country(String name){
        this.name = name;
    }
 
    public String getName(){ return name; }
    public void setName(String name) {this.name = name;}
 
    public String getCapital() {return capital;}
    public void setCapital(String capital) {this.capital = capital;}

    public Date getIndependenceDay() {return independenceDay;}
    public void setIndependenceDay(Date independenceDay) {this.independenceDay = independenceDay;}

    public long getPopulation() { return population; }
    public void setPopulation(long population) {this.population = population; }

    @Override
    public String toString() {
        return "Country{" + "capital=" + working capital missive of the alphabet + ",
               population=" + population + ",
               independenceDay=" + independenceDay + '}';

    }

    public void setIndependenceDay(String date) {
        DateFormat format = new SimpleDateFormat("dd/MM/yyyy");
        try {
            this.independenceDay = format.parse(date);
        } catch (ParseException ex) {
            Logger.getLogger(Country.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
   

   public static void main(String args[]){
            Country Republic of Republic of India = new Country("India");
            India.setCapital("New Delhi");
            India.setIndependenceDay("15/07/1947");
            India.setPopulation(1200000000);
           
            System.out.println(India);      
   }

}

toString method created past times Netbeans IDE
toString method generated past times Netbeans IDE create next output for higher upwards cast :

Country{capital=New Delhi, population=1200000000, independenceDay=Fri Aug xv 00:00:00 VET 1947}

If yous hold back at higher upwards output yous honour that NetBeans does non generated formatted Date for you, instead it calls toString() method of java.util.Date class.

toString() code generated past times Eclipse IDE:

By default Eclipse generates next toString method :

@Override
    public String toString() {
        return "Country [name=" + advert + ", capital=" + capital
                + ", population=" + population + ", independenceDay="
                + independenceDay + "]";
    }

You tin generate code for toString method inwards Eclipse past times clicking Source --Generate toString(). It too furnish several options similar choosing code mode e.g. concatenation operator or StringBuffer etc. Here is the output of toString() method nosotros only created past times Eclipse :

Country [name=India, capital=New Delhi, population=1200000000, independenceDay=Tue Jul 15 00:00:00 VET 1947]

Using ToStringBuilder for overriding Java toString method

Along alongside many useful classes similar PropertyUtils, EqualsBuilder or HashCodeBuilder; Apache park provides roughly other jewel called ToStringBuilder which tin generate code for toString() method inwards unlike styles. Let’s how does output of toString method looks similar inwards elementary mode as well as multi-line style.

Simple Style:
India,New Delhi,1200000000,Fri Aug 15 00:00:00 VET 1947

Multi-line style:
test.Country@f0eed6[
  name=India
  capital=New Delhi
  population=1200000000
  independenceDay=Fri Aug 15 00:00:00 VET 1947
]

NO_FIELD_NAMES_STYLE
test.Country@1d05c81[India,New Delhi,1200000000,Fri Aug 15 00:00:00 VET 1947]

SHORT_PREFIX_STYLE
Country[name=India,capital=New Delhi,population=1200000000,independenceDay=Fri Aug 15 00:00:00 VET 1947]

ToStringStyle.DEFAULT_STYLE
test.Country@1d05c81[name=India,capital=New Delhi,population=1200000000,independenceDay=Fri Aug 15 00:00:00 VET 1947]

Similarly Google’s opened upwards beginning library Guava too furnish convenient API to generate code for toString method inwards Java.

When toString method is invoked inwards Java

toString is a rather special method as well as invoked past times many Java API methods similar println(), printf(), loggers, assert statement, debuggers inwards IDE, piece printing collections as well as alongside concatenation operator. If subclass doesn't override toString() method than default implementation defined inwards Object cast gets invoked. Many programmers either utilization logging API similar Log4J or java.util.Logger to impress logs as well as oft transcend Object there.  logger.info("Customer non flora : " + customer) as well as if Customer doesn't override toString as well as impress meaningful information similar customerId, customerName etc than it would last hard to diagnose the problem. This why its ever proficient to override toString inwards Java.let's run into roughly benefits of doing this.

Benefits of overriding toString method:

1) As discussed above, correctly overridden toString helps inwards debugging past times printing meaningful information.

2) If value objects are stored inwards Collection than printing collection volition invoke toString on stored object which tin impress rattling useful information.One of the classic illustration of non overriding toString method is Array inwards Java, which prints default implementation rather than contents of array. Though at that spot are brace of ways to impress contents of array using Arrays.toString() etc but given Array is an object inwards Java, would bring been much amend if Array know how to impress itself much similar Collection classes similar List or Set.

3) If yous are debugging Java programme inwards Eclipse than using sentry or inspect characteristic to hold back object, toString volition definitely assistance you.

These are only roughly of the benefits yous acquire past times implementing or overriding toString method inwards Java, at that spot are many to a greater extent than which yous acquire as well as larn past times yourself. I promise these tips volition assistance yous to acquire most of your toString implementation. Let us know  if yous whatever unique toString() tips which has helped yous inwards your Java application.

Further Learning
Complete Java Masterclass
4 ways to compare String inwards Java

Why String is immutable inwards Java

Why String is a pop HashMap fundamental inwards Java

How SubString industrial plant inwards Java

How to carve upwards String inwards Java

How to supplant String using regular aspect inwards Java