CODEWITHSUNDEEP
javahashmap
DanH.
DanH.

Reputation: 53

Using HashMap with custom object in Java

I'm trying to use the following code to create HashMap of custom Objects.

public static void test() {
    programStats ps = new programStats();
    programStats ps1 = new programStats();
    List<programStats> psList = new LinkedList<programStats>();

    ps.progName = "test1";  
    ps1.progName= "Test11";

    psList.clear();
    psList.add(ps);

    Map<String,List<programStats>> d = new HashMap<String, List<programStats>>();
    d.put("Test1", psList);

    psList.add(ps1);
    for (programStats p : d.get("Test1")) {
        System.out.println(p.progName);
    }


class  programStats {
        public static String progName, module;
        public static int min, max,  mean,  mid, count;
        public static List<Integer> data = new ArrayList<Integer>();;
}

I have noticed that when I'm setting the value to ps1, the value of ps is changing too.

What am I doing wrong?

Upvotes: 1

Views: 113

Answers (1)

Mureinik
Mureinik

Reputation: 311143

All the members of your programStats class are static, meaning they belong to the class, not a specific instance. So, regardless of which instance you use to modify them, those values would be visible via any instance. You should change them to instance members:

class  programStats {
    // Note: The member are no longer static:
    public String progName, module;
    public int min, max,  mean,  mid, count;
    public List<Integer> data = new ArrayList<Integer>();
}

Upvotes: 2

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