这个问题通常比较常见在64位计算机上或使用大小超过1-2 GB的文件，并且与堆空间无关。切换到BufferedReader它应该可以正常工作，

This issue is usually more common on 64 bit machines or with files having size more than 1-2 GB and does not have anything to do with heap space. Switch to BufferedReader it should work fine,

BufferedReader br = new BufferedReader(new FileReader(filepath));
String line = "";
while((line=br.readLine())!=null)
{
    // do something
}