Java regex returns only single match

I have file with content:

~LayerData
type="waypointlist"
type="waypointlistend"
type="track" name="Track1" color=#695cbb
type="trackpoint" latitude="43.5032064" longitude="16.4266248"
type="trackpoint" latitude="43.5071074767561" longitude="16.48329290000057"
type="trackend"
~EndLayerData
~LayerData
type="waypointlist"
type="waypointlistend"
type="track" name="Track2" color=#000000
type="trackpoint" latitude="43.51037193515589" longitude="16.491883500895977"
type="trackpoint" latitude="43.521582832754135" longitude="16.473187288140295"
type="trackend"
~EndLayerData

I'm extracing LayerData -> EndLayerData matches using:

Pattern p = Pattern.compile("(~LayerData(.|\n)*~EndLayerData)");
Matcher m = p.matcher(s);

As a result I get m.group() with three items: first two are identical and contain the complete file. Last one is "\n". I expected to receive Track1 and Track2 separated.

You could match LayerData followed by all lines that do not start with either LayerData or EndLayerData using a negative lookahead.

^~LayerData(?:\R(?!~(?:End)?LayerData).*)*\R~EndLayerData

Explanation

• ^~LayerData Match LayerData from the start of the string
• (?: Non capture group
  • \R(?!~(?:End)?LayerData) Match a newline, assert what is directly to the right is not EndLayerData or LayerData
  • .* Match the rest of the line
• )* Close the group and repeat 0+ times to get all lines
• \R~EndLayerData Match a newline and EndLayerData

In Java with double escaped backslashes:

String regex = "^~LayerData(?:\\R(?!~(?:End)?LayerData).*)*\\R~EndLayerData";

Regex demo | Java demo

Example code

String regex = "^~LayerData(?:\\R(?!~(?:End)?LayerData).*)*\\R~EndLayerData";
String string = "...";

Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE);
Matcher matcher = pattern.matcher(string);

while (matcher.find()) {
    System.out.println(matcher.group(0));
}

Try this pattern

(~LayerData(.|\n)*?~EndLayerData)

Update:
Use Code Generator under tools in regex101 to get language-specific regex.

String regex = "\\~LayerData(.|\\n)*?\\~EndLayerData";
Pattern pattern = Pattern.compile(regex); 
Matcher matcher = pattern.matcher(string); 
while (matcher.find()) { 
System.out.println(matcher.group(0)); 
}

Earlier Answer:
You are not getting the match properly as the regex you are using is not proper. Since it matches with everything that starts with "~LayerData" and ends with "~EndLayerData", the whole file is getting matched. Creating an appropriate regex using regex101.com (helps in visualizing) and using that should fix the issue.