Kevin Chen kevinmichaelchen

ThreadLocal is a common cause of memory leaks in JVMs. In this post, we take a look under the hood to better understand what's going on.

Some background info, first. We have a superhero Wiki site with two portals in it: Batman and Superman.

public enum SuperheroPortal { BATMAN, SUPERMAN; }

Everything in the service layer depends on the currently selected portal.

	<filter class="com.mypackage.CustomWordDelimiterFilterFactory"
	catenateOverApostrophe="1"
	preserveOriginalApostropheWord="1"
	catenateOverHyphen="0"
	/>

	public class AggregateTextFromFiles {
	public static void main(String[] args) {
	List<File> pieces = getFilePiecesInDirectory();
	StringBuilder sb = new StringBuilder();
	for ( File piece : pieces )
	{
	String pieceText = new String( Files.readAllBytes( Paths.get( piece.getPath() ) ) );
	sb.append( pieceText );
	}
	String all = sb.toString();

	import com.google.gson.Gson;
	import org.junit.Before;
	import org.junit.Test;
	import org.junit.runner.RunWith;
	import org.springframework.context.annotation.Configuration;
	import org.springframework.http.MediaType;
	import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
	import org.springframework.stereotype.Controller;
	import org.springframework.test.context.ContextConfiguration;
	import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

	# A list of mail headers to test against

	# Outlook
	Content-disposition: attachment;
	filename=";;;.txt"


	# Outlook
	Content-disposition: attachment;
	filename*=UTF-8''%3B%E6%BC%A2%D8%B1%D9%82%D9%84%20%3B%3BDonaldTrump%E6%BC%A2%D8%B1%D9%82%D9%84%20%E6%BC%A2%D8%B1%D9%82%D9%84%20%E6%BC%A2%D8%B1%D9%82%D9%84%20%E6%BC%A2%D8%B1%D9%82%D9%84%20%E6%BC%A2%D8%B1%D9%82%D9%84%20%E6%BC%A2%D8%B1%D9%82%D9%84%20longTheDonald.txt

	class Test {
	public static void main( String[] args )
	{
	final String contentDisposition = "name: Content-Disposition\n" +
	"value: attachment;\n" +
	"\tsize=1123785;\n" +
	"\tmodification-date=\"Thu, 20 Aug 2015 17:27:44 GMT\";\n" +
	"\tfilename*0=\"=?utf-8?B?TmltciAoNCDDlyA0KSBhbmQgKDYgw5cgNikgaGlnaCBtb2JpbGl0eS\";\n" +
	"\tfilename*1=\"B2ZWhp?= cles.pdf\";\n" +
	"\tcreation-date=\"Thu, 20 Aug 2015 17:27:44 GMT\"";

	class Test {
	public static void main(String[] args) {
	Pattern pattern = Pattern.compile( "filename\\*\\d+" );
	System.out.println( pattern.matcher( "filename1" ).find() ); // false
	System.out.println( pattern.matcher( "filename*1" ).find() ); // true
	System.out.println( pattern.matcher( "filename*12" ).find() ); // true
	System.out.println( pattern.matcher( "filename**12" ).find() ); // false
	System.out.println( pattern.matcher( "filenamme*12" ).find() ); // false
	System.out.println( pattern.matcher( " filename**12 =" ).find() ); // false
	System.out.println( pattern.matcher( " filename**12=" ).find() ); // false

	import java.util.*;

	public class Test {

	public static void main(String[] args) {

	try {
	for (int i = 0; i < 10; i++) {
	System.out.println(i);
	if (i == 5) {

	public class Test {
	public static void main(String[] args) throws Exception
	{
	final String path = "/Users/kevinchen/Desktop/";

	final String html = new String( Files.readAllBytes( Paths.get( path + "beforeSanitize.html" ) ) );

	final String clean =
	Jsoup.clean( html,
	Whitelist.relaxed()