How to add an object in my collection by only using add method?
14,069
public class DataCollection implements java.io.Serializable{
private String Name;
private String Address;
private int Age;
public DataCollection(String name, String address, int age){
this.Name=name;
this.Address=address;
this.Age=age;
}
}
After that create DataCollection
objects:
DataCollection d1 = new DataCollection("nik", "10/5 cross", 20);//creation of List collection
Now put the object inside a collection:
List<DataCollection> list = new LinkedList<DataCollection>();
list.add(d1);
You can iterate like below:
List<DataCollection> list=new LinkedList<DataCollection>();
for(DataCollection d : list){
System.out.println(d);
}
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Author by
user2988935
Updated on September 27, 2022Comments
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user2988935 over 1 year
I have to create a collection of Name,Address,Age.How do I create this as a collection object in java.
My snippet is as follows:
public class DataCollection implements java.io.Serializable{ private String Name; private String Address; private int Age; }
And I have the getter and setter methods...
In the main method, how do I create this as a collection??
list.add(new DataCollection(??????) );
Can someone please help me on this?
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Danny over 10 yearsOff topic. In the future you should start classes with an uppercase letter (e.g.
DataCollection
)
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user2988935 over 10 years@Shreyos,@blubob.. based on your answers, I have updated my code as shown below: Please correct if my understanding is wrong.
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Gilbert Le Blanc over 10 yearsNo. You instantiate a List with an ArrayList or LinkedList. List<DataCollection> list = new ArrayList<DataCollection>(); You instantiate to an interface when you can. You instantiate to a concrete class when there is no interface or you need to use a method in the concrete class.
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user2988935 over 10 yearsimport java.util.ArrayList; import java.util.List; public final String getName() public final String getAddress() public final int Age() public final void setName(String aName) public final void setAddress(String aAddress) public final void setAge(int aAge) Main Mthod: List<DataCollection> list = new ArrayList<DataCollection>(); DataCollection dataCollection = new DataCollection(); dataCollection .setName("John"); dataCollection .setAddress("Chicago"); dataCollection .setAge(21); list.adddataCollection();
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user2988935 over 10 yearsWhen I try to use LinkedList it gives me error like LinkedList is not generic.It cannot be parameterizec with arguments<DataCollection>.
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Trying over 10 years@user2988935 You have to import this two:
import java.util.LinkedList;
import java.util.List;
. Make sure you use thisLinkedList
rather than some arbitrary implementation. -
user2988935 over 10 years@Trying... Thanks a lot. Is there a way to check the objects in the collection? I am using the list.get(i) but it returns the index. Is there anyway I can get the value ?
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Trying over 10 years@user2988935 see the edit in the answer.
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user2988935 over 10 yearsYes I tried. But I get the arbitrary values like ecd55fca,fa79750e,57b9a57,c83bc96b.... whereas the actual values are different. Kindly help.
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blueblob over 10 yearsYou are printing a pointer to the object. try
System.out.println(d.getName())
or override thetoString()
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Trying over 10 years@user2988935 override toString() method in the class
DataCollection
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user2988935 over 10 yearsThank you so much everyone..@Trying,@bluebob,@Danny,@Ian,@Shreyas.... It worked :-)
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user2988935 over 10 yearsI am sorry... one more question. How can I add these of objects in Map.. If i give map.update(key,list) will it work?
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user2988935 over 10 yearsWhen I try to do it, it shows me ClassNotFoundException. My classpath is all set with correct jars but still the error is shown...
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user2988935 over 10 yearsThis is after adding the Map...