import java.util.regex.*;
import java.lang.*;
 
class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
String str = "STARTText blah, blah\n" + 
"\\    next line with more text, but the leading backslash\n" + 
"\\    next line with more text, but the leading backslash\n" + 
"\\    next line with more text, but the leading backslash\n" + 
"foo\n" + 
"bar\n";
 
Pattern p = Pattern.compile("(?m)^STARTText.*?(\\r?\\n)(?:^\\\\.*?\\1)+");    
Matcher m = p.matcher(str);
if (m.find())
   System.out.printf("Matched: %s%n", m.group(0));
	}
}

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