Question

I have problem with filling a Map in Java, I think this is simple, but I can’t resolve this.

Let’s look at this:

Map<Integer, HashMap<String, String>> lineArrayData = new HashMap<Integer, HashMap<String, String>>();
HashMap<String, String> map = new HashMap<String, String>();

String singleData[];

int lineCounter = 0;
for ( String line : this.lines )
{
    singleData = line.split("\\|\\|");

    map.put("type", singleData[0]);
    map.put("text", singleData[1]);
    map.put("page", singleData[2]);
    map.put("x", singleData[3]);
    map.put("y", singleData[4]);

    lineArrayData.put(lineCounter, map);

    lineCounter++;
}

System.out.println(lineArrayData);

I have input

barcode||testowy test||1||100||100
text||texttstdasd||2||500||300

and my output is:

{0={text=texttstdasd, page=2, type=text, y=300, x=500}, 1={text=texttstdasd, page=2, type=text, y=300, x=500}}

what have I done wrong?

Answer 1

Move the following line inside the loop:

HashMap<String, String> map = new HashMap<String, String>();

Otherwise every iteration modifies the same inner map. The end result is that the outer map contains multiple references to the same inner map.

Here is the corrected version:

for ( String line : this.lines )
{
    HashMap<String, String> map = new HashMap<String, String>();
    singleData = line.split("\\|\\|");
    ...