Java: array attribute in object

Question

I am a newbie in Java programming and was just wondering if you can do this: I have a object class Person:

public class Person {

    public String name;
    public String[] friends;
}

If yes how to initialse it, i.e.

newPerson.name = "Max"; 
newPerson.friends = {"Tom", "Mike"};

I tried to do it like that, but it does not work.

You need to create an instance first. ```Person p = new Person();``` — NeplatnyUdaj, Jan 08 '14 at 20:42
If you are a newbie, then start by studying Java tutorials. You can't expect to learn Java by asking 500 questions on SO. — Marko Topolnik, Jan 08 '14 at 20:43

Ashish · Accepted Answer · 2014-01-08T20:51:19.753

10

try this

new Person("Max", new String[]{"Tom", "Mike"});

You would also need a constructor to initialize the variables.

public Person(String name, String[] friends){
    this.name = name;
    this.friends = friends;
}

As a good practice, you should also limit the access level of variables in your class to be private. (unless there is a very good reason to make them public.)

edited Jan 08 '14 at 20:51

answered Jan 08 '14 at 20:43

Ashish

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+1 for suggesting a constructor. You may want to mention that making fields public is not a good practice. – Sergey Kalinichenko Jan 08 '14 at 20:46
have a look http://stackoverflow.com/questions/7622730/why-are-instance-variables-in-java-are-always-private – Ashish Jan 08 '14 at 21:06

score 1 · Answer 2 · answered Jan 08 '14 at 20:43

1

try

newPerson.friends = new String[]{"Tom", "Mike"}

answered Jan 08 '14 at 20:43

Eugen Halca

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score 1 · Answer 3 · answered Jan 08 '14 at 20:43

You can do it like this

public static class Person {
    public String name;      
    public String[] friends;
}
public static void main(String[] args) {
    Person newPerson = new Person();
    newPerson.name = "Max";
    newPerson.friends = new String[] {"Tom", "Mike"};
}

score 1 · Answer 4 · answered Jan 08 '14 at 20:48

Thats actually pretty simple

U can initialize in creation (thats the easiest method):

public class Person {

      public String name = "Max";
      public String[] friends = {"Adam","Eve"};
 }

U could initialize variables in your constructor

public class Person {
      public String name;
      public String[] friends;
      public Person(){
          name =  "Max";
          friends = new String[] {"Adam", "Eve"};
      }
 }

Java: array attribute in object

4 Answers4